[PATCH 2/7] drm/dp_mst: Register AUX devices for MST ports
Lyude Paul
lyude at redhat.com
Mon Jul 1 20:43:44 UTC 2019
On Thu, 2019-06-27 at 22:21 +0000, Li, Sun peng (Leo) wrote:
> Sorry for the late response! just jumping back on this now.
>
> On 2019-05-16 5:40 p.m., Lyude Paul wrote:
> > [CAUTION: External Email]
> >
> > So a couple of things:
> >
> > On Thu, 2019-05-16 at 11:17 -0400, sunpeng.li at amd.com wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > >
> > > All available downstream ports - physical and logical - are exposed for
> > > each MST device. They are listed in /dev/, following the same naming
> > > scheme as SST devices by appending an incremental ID.
> > >
> > > Although all downstream ports are exposed, only some will work as
> > > expected. Consider the following topology:
> > >
> > > +---------+
> > > | ASIC |
> > > +---------+
> > > Conn-0|
> > > |
> > > +----v----+
> > > +----| MST HUB |----+
> > > | +---------+ |
> > > | |
> > > |Port-1 Port-2|
> > > +-----v-----+ +-----v-----+
> > > | MST | | SST |
> > > | Display | | Display |
> > > +-----------+ +-----------+
> > > |Port-1
> > > x
> > >
> > > MST Path | MST Device
> > > ----------+----------------------------------
> > > sst:0 | MST Hub
> > > mst:0-1 | MST Display
> > > mst:0-1-1 | MST Display's disconnected DP out
> > > mst:0-1-8 | MST Display's internal sink
> > > mst:0-2 | SST Display
> > >
> > > On certain MST displays, the upstream physical port will ACK DPCD reads.
> > > However, reads on the local logical port to the internal sink will
> > > *NAK*. i.e. reading mst:0-1 ACKs, but mst:0-1-8 NAKs.
> > >
> > > There may also be duplicates. Some displays will return the same GUID
> > > when reading DPCD from both mst:0-1 and mst:0-1-8.
> > >
> > > There are some device-dependent behavior as well. The MST hub used
> > > during testing will actually *ACK* read requests on a disconnected
> > > physical port, whereas the MST displays will NAK.
> > >
> > > In light of these discrepancies, it's simpler to expose all downstream
> > > ports - both physical and logical - and let the user decide what to use.
> > >
> > > Cc: Lyude Paul <lyude at redhat.com>
> > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > Signed-off-by: Leo Li <sunpeng.li at amd.com>
> > > ---
> > > drivers/gpu/drm/drm_dp_aux_dev.c | 14 ++++-
> > > drivers/gpu/drm/drm_dp_mst_topology.c | 103
> > > +++++++++++++++++++++++++++++
> > > -----
> > > include/drm/drm_dp_helper.h | 4 ++
> > > include/drm/drm_dp_mst_helper.h | 6 ++
> > > 4 files changed, 112 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > index 6d84611..01c02b9 100644
> > > --- a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > @@ -34,6 +34,7 @@
> > > #include <linux/uaccess.h>
> > > #include <linux/uio.h>
> > > #include <drm/drm_dp_helper.h>
> > > +#include <drm/drm_dp_mst_helper.h>
> > > #include <drm/drm_crtc.h>
> > > #include <drm/drmP.h>
> > >
> > > @@ -114,6 +115,7 @@ static ssize_t name_show(struct device *dev,
> > >
> > > return res;
> > > }
> > > +
> > > static DEVICE_ATTR_RO(name);
> > >
> > > static struct attribute *drm_dp_aux_attrs[] = {
> > > @@ -160,7 +162,11 @@ static ssize_t auxdev_read_iter(struct kiocb *iocb,
> > > struct iov_iter *to)
> > > break;
> > > }
> > >
> > > - res = drm_dp_dpcd_read(aux_dev->aux, pos, buf, todo);
> > > + if (aux_dev->aux->is_remote)
> > > + res = drm_dp_mst_dpcd_read(aux_dev->aux, pos, buf,
> > > todo);
> > > + else
> > > + res = drm_dp_dpcd_read(aux_dev->aux, pos, buf,
> > > todo);
> > > +
> >
> > It's still not at all clear to me why we're trying to avoid specifying
> > actual
> > callbacks for the aux device. We should remove this part entirely, remove
> > the
> > is_remote entry from struct drm_dp_aux, and then just specify our own hook
> > in
> > struct drm_dp_aux->transfer().
> >
>
> I'm not sure if this would work well. The existing policy does retries
> around the ->transfer() call. Using the same hook will cause a nested
> retry - once when calling remote_aux->transfer, and another when calling
> real_aux->transfer. The difference is the scope of the retry. The former
> replays the entire aux transaction, while the latter replays just the
> failed sideband packet. I think having the retry at the packet level
> makes more sense. Either way, it shouldn't happen in a nested manner.
>
> In general, we need a way to determine whether a message needs to be
> sent via sideband. I'm not sure if there's a better way than setting a
> 'is_remote' flag?
oh-this is a very good point actually! I suppose we would certainly want to be
able to retry on a packet level instead. Since that's the case, I think going
with the current is_remote solution should be fine then. Might be worth noting
the reasoning behind this with a comment
>
> Leo
>
> > > if (res <= 0)
> > > break;
> > >
> > > @@ -207,7 +213,11 @@ static ssize_t auxdev_write_iter(struct kiocb
> > > *iocb,
> > > struct iov_iter *from)
> > > break;
> > > }
> > >
> > > - res = drm_dp_dpcd_write(aux_dev->aux, pos, buf, todo);
> > > + if (aux_dev->aux->is_remote)
> > > + res = drm_dp_mst_dpcd_write(aux_dev->aux, pos,
> > > buf,
> > > todo);
> > > + else
> > > + res = drm_dp_dpcd_write(aux_dev->aux, pos, buf,
> > > todo);
> > > +
> > > if (res <= 0)
> > > break;
> > >
> > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > index 2ab16c9..54da68e 100644
> > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > @@ -35,6 +35,8 @@
> > > #include <drm/drm_atomic_helper.h>
> > > #include <drm/drm_crtc_helper.h>
> > >
> > > +#include "drm_crtc_helper_internal.h"
> > > +
> >
> > Unless I'm mistaken, this looks like some sort of ditritus.
> >
> > > /**
> > > * DOC: dp mst helper
> > > *
> > > @@ -52,6 +54,9 @@ static int drm_dp_dpcd_write_payload(struct
> > > drm_dp_mst_topology_mgr *mgr,
> > > int id,
> > > struct drm_dp_payload *payload);
> > >
> > > +static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> > > + struct drm_dp_mst_port *port,
> > > + int offset, int size, u8 *bytes);
> > > static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
> > > struct drm_dp_mst_port *port,
> > > int offset, int size, u8 *bytes);
> > > @@ -941,6 +946,8 @@ static void drm_dp_destroy_port(struct kref *kref)
> > > struct drm_dp_mst_topology_mgr *mgr = port->mgr;
> > >
> > > if (!port->input) {
> > > + drm_dp_aux_unregister_devnode(&port->aux);
> > > +
> > > port->vcpi.num_slots = 0;
> > >
> > > kfree(port->cached_edid);
> > > @@ -1095,6 +1102,46 @@ static bool drm_dp_port_setup_pdt(struct
> > > drm_dp_mst_port *port)
> > > return send_link;
> > > }
> > >
> > > +/**
> > > + * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via
> > > sideband
> > > + * @aux: Fake sideband AUX CH
> > > + * @offset: address of the (first) register to read
> > > + * @buffer: buffer to store the register values
> > > + * @size: number of bytes in @buffer
> > > + *
> > > + * Performs the same functionality for remote devices via
> > > + * sideband messaging as drm_dp_dpcd_read() does for local
> > > + * devices via actual AUX CH.
> > > + */
> > > +ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
> > > + unsigned int offset, void *buffer, size_t
> > > size)
> > > +{
> > > + struct drm_dp_mst_port *port = container_of(aux, struct
> > > drm_dp_mst_port, aux);
> > > +
> > > + return drm_dp_send_dpcd_read(port->mgr, port,
> > > + offset, size, buffer);
> > > +}
> > > +
> > > +/**
> > > + * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via
> > > sideband
> > > + * @aux: Fake sideband AUX CH
> > > + * @offset: address of the (first) register to write
> > > + * @buffer: buffer containing the values to write
> > > + * @size: number of bytes in @buffer
> > > + *
> > > + * Performs the same functionality for remote devices via
> > > + * sideband messaging as drm_dp_dpcd_write() does for local
> > > + * devices via actual AUX CH.
> > > + */
> > > +ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
> > > + unsigned int offset, void *buffer, size_t
> > > size)
> > > +{
> > > + struct drm_dp_mst_port *port = container_of(aux, struct
> > > drm_dp_mst_port, aux);
> > > +
> > > + return drm_dp_send_dpcd_write(port->mgr, port,
> > > + offset, size, buffer);
> > > +}
> > > +
> > > static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8
> > > *guid)
> > > {
> > > int ret;
> > > @@ -1158,6 +1205,7 @@ static void drm_dp_add_port(struct
> > > drm_dp_mst_branch
> > > *mstb,
> > > port->mgr = mstb->mgr;
> > > port->aux.name = "DPMST";
> > > port->aux.dev = dev->dev;
> > > + port->aux.is_remote = true;
> > > created = true;
> > > } else {
> > > old_pdt = port->pdt;
> > > @@ -1188,7 +1236,7 @@ static void drm_dp_add_port(struct
> > > drm_dp_mst_branch
> > > *mstb,
> > > drm_dp_send_enum_path_resources(mstb-
> > > >mgr,
> > > mstb, port);
> > > } else {
> > > port->available_pbn = 0;
> > > - }
> > > + }
> > > }
> > >
> > > if (old_pdt != port->pdt && !port->input) {
> > > @@ -1220,6 +1268,8 @@ static void drm_dp_add_port(struct
> > > drm_dp_mst_branch
> > > *mstb,
> > > drm_connector_set_tile_property(port->connector);
> > > }
> > > (*mstb->mgr->cbs->register_connector)(port->connector);
> >
> > This is wrong: we always want to setup everything in the connector first
> > before trying to register it, not after. Otherwise, things explode like
> > so:
> >
> > [ 13.305329] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (3)
> > [ 13.305361] [drm:drm_mode_object_get [drm]] OBJ ID: 123 (1)
> > [ 13.305384] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (4)
> > [ 13.305405] [drm:drm_mode_object_get [drm]] OBJ ID: 124 (1)
> > [ 13.305429] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (5)
> > [ 13.305449] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (6)
> > [ 13.305471] [drm:drm_mode_object_get [drm]] OBJ ID: 85 (5)
> > [ 13.305490] [drm:drm_mode_object_get [drm]] OBJ ID: 85 (6)
> > [ 13.305512] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (6)
> > [ 13.305532] [drm:drm_mode_object_get [drm]] OBJ ID: 85 (5)
> > [ 13.305552] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (5)
> > [ 13.305571] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (6)
> > [ 13.305592] [drm:drm_mode_object_get [drm]] OBJ ID: 86 (5)
> > [ 13.305612] [drm:drm_mode_object_get [drm]] OBJ ID: 86 (6)
> > [ 13.305631] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (6)
> > [ 13.305651] [drm:drm_mode_object_get [drm]] OBJ ID: 86 (5)
> > [ 13.305725] [drm:drm_vblank_enable [drm]] enabling vblank on crtc 0,
> > ret: 0
> > [ 13.305768] [drm:drm_vblank_enable [drm]] enabling vblank on crtc 1,
> > ret: 0
> > [ 13.306088] [drm:drm_handle_vblank [drm]] vblank event on 325, current
> > 325
> > [ 13.322514] [drm:drm_handle_vblank [drm]] vblank event on 313, current
> > 313
> > [ 13.322612] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (6)
> > [ 13.322634] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (5)
> > [ 13.322656] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (6)
> > [ 13.322676] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (5)
> > [ 13.322697] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 123 (2)
> > [ 13.322718] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 124 (2)
> > [ 13.322740] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (5)
> > [ 13.322764] [drm:vblank_disable_fn [drm]] disabling vblank on crtc 0
> > [ 13.322784] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (4)
> > [ 13.339191] [drm:vblank_disable_fn [drm]] disabling vblank on crtc 1
> > [ 451.149789] Console: switching to colour dummy device 80x25
> > [ 451.194596] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPDDC-A] unregistering
> > [ 451.194666] [drm:drm_sysfs_connector_remove [drm]] removing "eDP-1"
> > from sysfs
> > [ 451.194718] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPDDC-B] unregistering
> > [ 451.194766] [drm:drm_sysfs_connector_remove [drm]] removing "DP-1" from
> > sysfs
> > [ 451.194791] [drm:drm_sysfs_connector_remove [drm]] removing "HDMI-A-1"
> > from sysfs
> > [ 451.194835] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPDDC-C] unregistering
> > [ 451.194880] [drm:drm_sysfs_connector_remove [drm]] removing "DP-2" from
> > sysfs
> > [ 451.194903] [drm:drm_sysfs_connector_remove [drm]] removing "HDMI-A-2"
> > from sysfs
> > [ 451.194924] [drm:drm_sysfs_connector_remove [drm]] removing "DP-3" from
> > sysfs
> > [ 451.194950] [drm:drm_sysfs_connector_remove [drm]] removing "DP-4" from
> > sysfs
> > [ 451.194975] [drm:drm_sysfs_connector_remove [drm]] removing "DP-5" from
> > sysfs
> > [ 451.204535] [drm:drm_mode_object_get [drm]] OBJ ID: 123 (1)
> > [ 451.204551] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 123 (2)
> > [ 451.204566] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (3)
> > [ 451.204582] [drm:drm_mode_object_get [drm]] OBJ ID: 85 (5)
> > [ 451.204596] [drm:drm_mode_object_get [drm]] OBJ ID: 85 (6)
> > [ 451.204611] [drm:drm_mode_object_get [drm]] OBJ ID: 124 (1)
> > [ 451.204621] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 124 (2)
> > [ 451.204631] [drm:drm_mode_object_get [drm]] OBJ ID: 113 (4)
> > [ 451.204641] [drm:drm_mode_object_get [drm]] OBJ ID: 86 (5)
> > [ 451.204651] [drm:drm_mode_object_get [drm]] OBJ ID: 86 (6)
> > [ 451.204662] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (6)
> > [ 451.204671] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (6)
> > [ 451.204680] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (5)
> > [ 451.204689] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (4)
> > [ 451.204699] [drm:drm_dp_mst_duplicate_state [drm_kms_helper]] port
> > 00000000dde1b00a (5)
> > [ 451.204703] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000dde1b00a (4)
> > [ 451.411817] [drm:intel_panel_actually_set_backlight [i915]] set
> > backlight PWM = 0
> > [ 451.420911] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-A: 0x00600
> > AUX <- (ret= 1) 02
> > [ 451.425358] [drm:gen8_de_irq_handler [i915]] hotplug event received,
> > stat 0x01000000, dig 0x11101010, pins 0x00000010, long 0x00000000
> > [ 451.425422] [drm:intel_hpd_irq_handler [i915]] digital hpd port A -
> > short
> > [ 451.471777] [drm:drm_dp_mst_topology_get_mstb_validated
> > [drm_kms_helper]] mstb 00000000eec1a629 (2)
> > [ 451.473361] [drm:gen8_de_irq_handler [i915]] hotplug event received,
> > stat 0x01000000, dig 0x12101010, pins 0x00000010, long 0x00000010
> > [ 451.473465] [drm:intel_hpd_irq_handler [i915]] digital hpd port A -
> > long
> > [ 452.207301] [drm:gen8_de_irq_handler [i915]] hotplug event received,
> > stat 0x01000000, dig 0x12101010, pins 0x00000010, long 0x00000010
> > [ 452.207395] [drm:intel_hpd_irq_handler [i915]] digital hpd port A -
> > long
> > [ 452.340311] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-A: 0x00000
> > AUX -> (ret= 15) 11 0a 02 41 00 00 01 00 02 00 00 00 00 0b 00
> > [ 452.341060] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-A: 0x00201
> > AUX -> (ret= 1) 00
> > [ 452.341584] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x01000
> > AUX <- (ret= 10) 10 47 d3 11 11 01 00 00 00 f4
> > [ 452.343183] [drm:gen8_de_irq_handler [i915]] hotplug event received,
> > stat 0x00200000, dig 0x10101011, pins 0x00000020, long 0x00000000
> > [ 452.343286] [drm:intel_hpd_irq_handler [i915]] digital hpd port B -
> > short
> > [ 452.344765] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x02002
> > AUX -> (ret= 14) 01 10 00 00 00 00 00 00 00 00 77 77 01 00
> > [ 452.346263] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x01400
> > AUX -> (ret= 16) 10 46 d6 11 10 01 00 00 78 00 00 00 00 00 00 00
> > [ 452.346287] [drm:drm_dp_get_mst_branch_device [drm_kms_helper]] mstb
> > 00000000eec1a629 (3)
> > [ 452.346305] [drm:drm_dp_mst_topology_put_mstb [drm_kms_helper]] mstb
> > 00000000eec1a629 (2)
> > [ 452.346405] [drm:drm_dp_mst_topology_put_mstb [drm_kms_helper]] mstb
> > 00000000eec1a629 (1)
> > [ 452.347529] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x02003
> > AUX <- (ret= 3) 10 00 00
> > [ 452.348672] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x002c0
> > AUX <- (ret= 1) 01
> > [ 452.350168] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x02002
> > AUX -> (ret= 14) 01 00 00 00 00 00 00 00 00 00 77 77 01 00
> > [ 452.351328] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x001c0
> > AUX <- (ret= 3) 01 01 00
> > [ 452.352665] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x002c0
> > AUX -> (ret= 1) 01
> > [ 452.358905] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x002c0
> > AUX -> (ret= 1) 01
> > [ 452.360327] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x002c0
> > AUX -> (ret= 1) 01
> > [ 452.361660] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x002c0
> > AUX -> (ret= 1) 03
> > [ 452.361681] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000dde1b00a (3)
> > [ 452.361700] [drm:drm_dp_mst_topology_get_port_validated
> > [drm_kms_helper]] port 00000000dde1b00a (2)
> > [ 452.362894] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x01000
> > AUX <- (ret= 6) 10 43 c7 25 10 c0
> > [ 452.364318] [drm:gen8_de_irq_handler [i915]] hotplug event received,
> > stat 0x00200000, dig 0x10101011, pins 0x00000020, long 0x00000000
> > [ 452.364421] [drm:intel_hpd_irq_handler [i915]] digital hpd port B -
> > short
> > [ 452.365929] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x02002
> > AUX -> (ret= 14) 01 10 00 00 00 00 00 00 00 00 77 77 01 00
> > [ 452.367361] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x01400
> > AUX -> (ret= 16) 10 43 c7 25 10 c0 00 00 00 00 00 00 00 00 00 00
> > [ 452.367388] [drm:drm_dp_get_mst_branch_device [drm_kms_helper]] mstb
> > 00000000eec1a629 (2)
> > [ 452.367407] [drm:drm_dp_mst_topology_put_mstb [drm_kms_helper]] mstb
> > 00000000eec1a629 (1)
> > [ 452.367460] [drm:drm_dp_mst_topology_put_port [drm_kms_helper]] port
> > 00000000dde1b00a (1)
> > [ 452.368548] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x02003
> > AUX <- (ret= 3) 10 00 00
> > [ 452.368803] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x00600
> > AUX <- (ret= 1) 02
> > [ 452.368970] [drm:intel_dump_cdclk_state [i915]] Changing CDCLK to
> > 337500 kHz, VCO 8100000 kHz, ref 24000 kHz, bypass 24000 kHz, voltage
> > level 0
> > [ 452.369269] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 123 (1)
> > [ 452.369330] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 124 (1)
> > [ 452.369422] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (5)
> > [ 452.369466] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (4)
> > [ 452.369515] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (5)
> > [ 452.369558] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (4)
> > [ 452.369608] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (3)
> > [ 452.369660] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (2)
> > [ 452.369690] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000dde1b00a (2)
> > [ 452.369750] [drm:drm_irq_uninstall [drm]] irq=177
> > [ 452.406452] [drm:drm_dp_dpcd_read [drm_kms_helper]] DPDDC-B: 0x02002
> > AUX -> (ret= 14) 01 00 00 00 00 00 00 00 00 00 00 00 80 00
> > [ 452.412626] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (3)
> > [ 452.412636] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 91 (2)
> > [ 452.412644] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 98 (2)
> > [ 452.412652] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 104 (2)
> > [ 452.412660] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 109 (2)
> > [ 452.412668] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (3)
> > [ 452.412676] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 117 (2)
> > [ 452.412684] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 120 (2)
> > [ 452.412692] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 85 (2)
> > [ 452.412700] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (2)
> > [ 452.412708] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 113 (1)
> > [ 452.424450] [drm:drm_dp_dpcd_write [drm_kms_helper]] DPDDC-B: 0x00111
> > AUX <- (ret= 1) 00
> > [ 452.424454] [drm:drm_dp_mst_topology_put_mstb [drm_kms_helper]] mstb
> > 00000000eec1a629 (0)
> > [ 452.424457] [drm:drm_dp_mst_topology_put_port [drm_kms_helper]] port
> > 00000000eeef3cfd (0)
> > [ 452.424461] ------------[ cut here ]------------
> > [ 452.424464] sysfs group 'power' not found for kobject 'drm_dp_aux5'
> > [ 452.424471] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.424473] Modules linked in: vfat fat elan_i2c i915(O) intel_rapl
> > x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt kvm
> > mei_wdt irqbypass iTCO_vendor_support crct10dif_pclmul wmi_bmof
> > intel_wmi_thunderbolt crc32_pclmul i2c_algo_bit ghash_clmulni_intel
> > intel_cstate drm_kms_helper(O) intel_uncore intel_rapl_perf btusb btrtl
> > btbcm syscopyarea btintel sysfillrect sysimgblt fb_sys_fops bluetooth
> > drm(O) joydev mei_me idma64 ucsi_acpi thunderbolt ecdh_generic i2c_i801
> > intel_xhci_usb_role_switch processor_thermal_device typec_ucsi
> > intel_lpss_pci intel_soc_dts_iosf mei roles intel_lpss typec
> > intel_pch_thermal wmi thinkpad_acpi ledtrig_audio rfkill int3403_thermal
> > int340x_thermal_zone int3400_thermal acpi_thermal_rel acpi_pad video
> > pcc_cpufreq crc32c_intel nvme serio_raw uas e1000e nvme_core usb_storage
> > i2c_dev
> > [ 452.424492] CPU: 3 PID: 1887 Comm: unloadgpumod Tainted:
> > G O 5.1.0Lyude-Test+ #1
> > [ 452.424494] Hardware name: LENOVO 20L8S2N800/20L8S2N800, BIOS N22ET35W
> > (1.12 ) 04/09/2018
> > [ 452.424496] RIP: 0010:sysfs_remove_group+0x76/0x80
> > [ 452.424498] Code: 48 89 df 5b 5d 41 5c e9 f8 bc ff ff 48 89 df e8 d0 bc
> > ff ff eb cb 49 8b 14 24 48 8b 75 00 48 c7 c7 08 a5 0c aa e8 44 00 d6 ff
> > <0f> 0b 5b 5d 41 5c c3 0f 1f 00 0f 1f 44 00 00 48 85 f6 74 31 41 54
> > [ 452.424500] RSP: 0018:ffffa8bb81b5fb28 EFLAGS: 00010282
> > [ 452.424501] RAX: 0000000000000000 RBX: 0000000000000000 RCX:
> > 0000000000000006
> > [ 452.424502] RDX: 0000000000000007 RSI: 0000000000000086 RDI:
> > ffff981fde2d5a00
> > [ 452.424503] RBP: ffffffffa9ea12e0 R08: 0000000000000792 R09:
> > 0000000000000046
> > [ 452.424504] R10: 0000000000000727 R11: ffffa8bb81b5f9d0 R12:
> > ffff981fd5f77010
> > [ 452.424505] R13: ffff981fd6ebbedc R14: dead000000000200 R15:
> > dead000000000100
> > [ 452.424507] FS: 00007f8cc1d8c740(0000) GS:ffff981fde2c0000(0000)
> > knlGS:0000000000000000
> > [ 452.424508] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 452.424509] CR2: 000055b19d079a08 CR3: 000000043b2a0002 CR4:
> > 00000000003606e0
> > [ 452.424510] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > 0000000000000000
> > [ 452.424511] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> > 0000000000000400
> > [ 452.424512] Call Trace:
> > [ 452.424516] device_del+0x75/0x360
> > [ 452.424518] ? class_find_device+0x96/0xf0
> > [ 452.424520] device_unregister+0x16/0x60
> > [ 452.424521] device_destroy+0x3a/0x40
> > [ 452.424525] drm_dp_aux_unregister_devnode+0xea/0x180 [drm_kms_helper]
> > [ 452.424534] ? drm_dbg+0x87/0x90 [drm]
> > [ 452.424538] drm_dp_mst_topology_put_port+0x5b/0x110 [drm_kms_helper]
> > [ 452.424543] drm_dp_mst_topology_put_mstb+0xb6/0x180 [drm_kms_helper]
> > [ 452.424547] drm_dp_mst_topology_mgr_set_mst+0x233/0x2b0
> > [drm_kms_helper]
> > [ 452.424551] drm_dp_mst_topology_mgr_destroy+0x18/0xa0 [drm_kms_helper]
> > [ 452.424571] intel_dp_encoder_flush_work+0x32/0xb0 [i915]
> > [ 452.424592] intel_ddi_encoder_destroy+0x32/0x70 [i915]
> > [ 452.424600] drm_mode_config_cleanup+0x51/0x2e0 [drm]
> > [ 452.424621] intel_modeset_cleanup+0xc8/0x140 [i915]
> > [ 452.424633] i915_driver_unload+0xa8/0x130 [i915]
> > [ 452.424645] i915_pci_remove+0x1e/0x40 [i915]
> > [ 452.424647] pci_device_remove+0x3b/0xc0
> > [ 452.424649] device_release_driver_internal+0xe4/0x1d0
> > [ 452.424651] pci_stop_bus_device+0x69/0x90
> > [ 452.424653] pci_stop_and_remove_bus_device_locked+0x16/0x30
> > [ 452.424655] remove_store+0x75/0x90
> > [ 452.424656] kernfs_fop_write+0x116/0x190
> > [ 452.424658] vfs_write+0xa5/0x1a0
> > [ 452.424660] ksys_write+0x57/0xd0
> > [ 452.424663] do_syscall_64+0x55/0x150
> > [ 452.424665] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [ 452.424667] RIP: 0033:0x7f8cc1e7d038
> > [ 452.424668] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00
> > f3 0f 1e fa 48 8d 05 e5 76 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05
> > <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
> > [ 452.424670] RSP: 002b:00007ffce4321218 EFLAGS: 00000246 ORIG_RAX:
> > 0000000000000001
> > [ 452.424672] RAX: ffffffffffffffda RBX: 0000000000000002 RCX:
> > 00007f8cc1e7d038
> > [ 452.424673] RDX: 0000000000000002 RSI: 000056515aefbf00 RDI:
> > 0000000000000001
> > [ 452.424674] RBP: 000056515aefbf00 R08: 000000000000000a R09:
> > 00007f8cc1f0ee80
> > [ 452.424675] R10: 000000000000000a R11: 0000000000000246 R12:
> > 00007f8cc1f50780
> > [ 452.424676] R13: 0000000000000002 R14: 00007f8cc1f4b740 R15:
> > 0000000000000002
> > [ 452.424678] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.424680] ---[ end trace a1c11eaf054910a3 ]---
> > [ 452.424751] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPMST] unregistering
> > [ 452.424755] [drm:drm_dp_mst_topology_put_port [drm_kms_helper]] port
> > 000000000f6aa5a3 (0)
> > [ 452.424765] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 120 (1)
> > [ 452.424770] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000eeef3cfd (1)
> > [ 452.424773] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000eeef3cfd (0)
> > [ 452.424776] [drm:drm_dp_mst_put_mstb_malloc [drm_kms_helper]] mstb
> > 00000000eec1a629 (4)
> > [ 452.424783] [drm:drm_sysfs_hotplug_event [drm]] generating hotplug
> > event
> > [ 452.424790] ------------[ cut here ]------------
> > [ 452.424791] sysfs group 'power' not found for kobject 'drm_dp_aux4'
> > [ 452.424795] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.424796] Modules linked in: vfat fat elan_i2c i915(O) intel_rapl
> > x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt kvm
> > mei_wdt irqbypass iTCO_vendor_support crct10dif_pclmul wmi_bmof
> > intel_wmi_thunderbolt crc32_pclmul i2c_algo_bit ghash_clmulni_intel
> > intel_cstate drm_kms_helper(O) intel_uncore intel_rapl_perf btusb btrtl
> > btbcm syscopyarea btintel sysfillrect sysimgblt fb_sys_fops bluetooth
> > drm(O) joydev mei_me idma64 ucsi_acpi thunderbolt ecdh_generic i2c_i801
> > intel_xhci_usb_role_switch processor_thermal_device typec_ucsi
> > intel_lpss_pci intel_soc_dts_iosf mei roles intel_lpss typec
> > intel_pch_thermal wmi thinkpad_acpi ledtrig_audio rfkill int3403_thermal
> > int340x_thermal_zone int3400_thermal acpi_thermal_rel acpi_pad video
> > pcc_cpufreq crc32c_intel nvme serio_raw uas e1000e nvme_core usb_storage
> > i2c_dev
> > [ 452.424809] CPU: 3 PID: 1887 Comm: unloadgpumod Tainted:
> > G W O 5.1.0Lyude-Test+ #1
> > [ 452.424811] Hardware name: LENOVO 20L8S2N800/20L8S2N800, BIOS N22ET35W
> > (1.12 ) 04/09/2018
> > [ 452.424812] RIP: 0010:sysfs_remove_group+0x76/0x80
> > [ 452.424813] Code: 48 89 df 5b 5d 41 5c e9 f8 bc ff ff 48 89 df e8 d0 bc
> > ff ff eb cb 49 8b 14 24 48 8b 75 00 48 c7 c7 08 a5 0c aa e8 44 00 d6 ff
> > <0f> 0b 5b 5d 41 5c c3 0f 1f 00 0f 1f 44 00 00 48 85 f6 74 31 41 54
> > [ 452.424815] RSP: 0018:ffffa8bb81b5fb28 EFLAGS: 00010282
> > [ 452.424816] RAX: 0000000000000000 RBX: 0000000000000000 RCX:
> > 0000000000000006
> > [ 452.424817] RDX: 0000000000000007 RSI: 0000000000000086 RDI:
> > ffff981fde2d5a00
> > [ 452.424818] RBP: ffffffffa9ea12e0 R08: 00000000000007d1 R09:
> > 0000000000000046
> > [ 452.424820] R10: 0000000000000727 R11: ffffa8bb81b5f9d0 R12:
> > ffff981fd50d0410
> > [ 452.424821] R13: ffff981fd6ebbebc R14: dead000000000200 R15:
> > dead000000000100
> > [ 452.424822] FS: 00007f8cc1d8c740(0000) GS:ffff981fde2c0000(0000)
> > knlGS:0000000000000000
> > [ 452.424823] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 452.424824] CR2: 000055b19d079a08 CR3: 000000043b2a0002 CR4:
> > 00000000003606e0
> > [ 452.424825] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > 0000000000000000
> > [ 452.424826] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> > 0000000000000400
> > [ 452.424827] Call Trace:
> > [ 452.424829] device_del+0x75/0x360
> > [ 452.424830] ? class_find_device+0x96/0xf0
> > [ 452.424832] device_unregister+0x16/0x60
> > [ 452.424833] device_destroy+0x3a/0x40
> > [ 452.424837] drm_dp_aux_unregister_devnode+0xea/0x180 [drm_kms_helper]
> > [ 452.424841] drm_dp_mst_topology_put_port+0x5b/0x110 [drm_kms_helper]
> > [ 452.424845] drm_dp_mst_topology_put_mstb+0xb6/0x180 [drm_kms_helper]
> > [ 452.424849] drm_dp_mst_topology_mgr_set_mst+0x233/0x2b0
> > [drm_kms_helper]
> > [ 452.424854] drm_dp_mst_topology_mgr_destroy+0x18/0xa0 [drm_kms_helper]
> > [ 452.424873] intel_dp_encoder_flush_work+0x32/0xb0 [i915]
> > [ 452.424892] intel_ddi_encoder_destroy+0x32/0x70 [i915]
> > [ 452.424900] drm_mode_config_cleanup+0x51/0x2e0 [drm]
> > [ 452.424920] intel_modeset_cleanup+0xc8/0x140 [i915]
> > [ 452.424932] i915_driver_unload+0xa8/0x130 [i915]
> > [ 452.424943] i915_pci_remove+0x1e/0x40 [i915]
> > [ 452.424945] pci_device_remove+0x3b/0xc0
> > [ 452.424947] device_release_driver_internal+0xe4/0x1d0
> > [ 452.424948] pci_stop_bus_device+0x69/0x90
> > [ 452.424950] pci_stop_and_remove_bus_device_locked+0x16/0x30
> > [ 452.424951] remove_store+0x75/0x90
> > [ 452.424953] kernfs_fop_write+0x116/0x190
> > [ 452.424954] vfs_write+0xa5/0x1a0
> > [ 452.424956] ksys_write+0x57/0xd0
> > [ 452.424957] do_syscall_64+0x55/0x150
> > [ 452.424959] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [ 452.424960] RIP: 0033:0x7f8cc1e7d038
> > [ 452.424961] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00
> > f3 0f 1e fa 48 8d 05 e5 76 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05
> > <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
> > [ 452.424963] RSP: 002b:00007ffce4321218 EFLAGS: 00000246 ORIG_RAX:
> > 0000000000000001
> > [ 452.424965] RAX: ffffffffffffffda RBX: 0000000000000002 RCX:
> > 00007f8cc1e7d038
> > [ 452.424966] RDX: 0000000000000002 RSI: 000056515aefbf00 RDI:
> > 0000000000000001
> > [ 452.424967] RBP: 000056515aefbf00 R08: 000000000000000a R09:
> > 00007f8cc1f0ee80
> > [ 452.424968] R10: 000000000000000a R11: 0000000000000246 R12:
> > 00007f8cc1f50780
> > [ 452.424969] R13: 0000000000000002 R14: 00007f8cc1f4b740 R15:
> > 0000000000000002
> > [ 452.424971] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.424972] ---[ end trace a1c11eaf054910a4 ]---
> > [ 452.424992] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPMST] unregistering
> > [ 452.424997] [drm:drm_dp_mst_topology_put_port [drm_kms_helper]] port
> > 00000000dde1b00a (0)
> > [ 452.425006] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 117 (1)
> > [ 452.425010] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 000000000f6aa5a3 (1)
> > [ 452.425014] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 000000000f6aa5a3 (0)
> > [ 452.425017] [drm:drm_dp_mst_put_mstb_malloc [drm_kms_helper]] mstb
> > 00000000eec1a629 (3)
> > [ 452.425023] [drm:drm_sysfs_hotplug_event [drm]] generating hotplug
> > event
> > [ 452.425028] ------------[ cut here ]------------
> > [ 452.425029] sysfs group 'power' not found for kobject 'drm_dp_aux3'
> > [ 452.425033] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.425034] Modules linked in: vfat fat elan_i2c i915(O) intel_rapl
> > x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt kvm
> > mei_wdt irqbypass iTCO_vendor_support crct10dif_pclmul wmi_bmof
> > intel_wmi_thunderbolt crc32_pclmul i2c_algo_bit ghash_clmulni_intel
> > intel_cstate drm_kms_helper(O) intel_uncore intel_rapl_perf btusb btrtl
> > btbcm syscopyarea btintel sysfillrect sysimgblt fb_sys_fops bluetooth
> > drm(O) joydev mei_me idma64 ucsi_acpi thunderbolt ecdh_generic i2c_i801
> > intel_xhci_usb_role_switch processor_thermal_device typec_ucsi
> > intel_lpss_pci intel_soc_dts_iosf mei roles intel_lpss typec
> > intel_pch_thermal wmi thinkpad_acpi ledtrig_audio rfkill int3403_thermal
> > int340x_thermal_zone int3400_thermal acpi_thermal_rel acpi_pad video
> > pcc_cpufreq crc32c_intel nvme serio_raw uas e1000e nvme_core usb_storage
> > i2c_dev
> > [ 452.425047] CPU: 3 PID: 1887 Comm: unloadgpumod Tainted:
> > G W O 5.1.0Lyude-Test+ #1
> > [ 452.425048] Hardware name: LENOVO 20L8S2N800/20L8S2N800, BIOS N22ET35W
> > (1.12 ) 04/09/2018
> > [ 452.425050] RIP: 0010:sysfs_remove_group+0x76/0x80
> > [ 452.425051] Code: 48 89 df 5b 5d 41 5c e9 f8 bc ff ff 48 89 df e8 d0 bc
> > ff ff eb cb 49 8b 14 24 48 8b 75 00 48 c7 c7 08 a5 0c aa e8 44 00 d6 ff
> > <0f> 0b 5b 5d 41 5c c3 0f 1f 00 0f 1f 44 00 00 48 85 f6 74 31 41 54
> > [ 452.425053] RSP: 0018:ffffa8bb81b5fb28 EFLAGS: 00010282
> > [ 452.425054] RAX: 0000000000000000 RBX: 0000000000000000 RCX:
> > 0000000000000006
> > [ 452.425055] RDX: 0000000000000007 RSI: 0000000000000086 RDI:
> > ffff981fde2d5a00
> > [ 452.425056] RBP: ffffffffa9ea12e0 R08: 000000000000080f R09:
> > 0000000000000046
> > [ 452.425057] R10: 0000000000000727 R11: ffffa8bb81b5f9d0 R12:
> > ffff981fd50d1810
> > [ 452.425058] R13: ffff981fd6ebbe1c R14: dead000000000200 R15:
> > dead000000000100
> > [ 452.425059] FS: 00007f8cc1d8c740(0000) GS:ffff981fde2c0000(0000)
> > knlGS:0000000000000000
> > [ 452.425061] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 452.425062] CR2: 000055b19d079a08 CR3: 000000043b2a0002 CR4:
> > 00000000003606e0
> > [ 452.425063] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > 0000000000000000
> > [ 452.425064] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> > 0000000000000400
> > [ 452.425065] Call Trace:
> > [ 452.425066] device_del+0x75/0x360
> > [ 452.425068] ? class_find_device+0x96/0xf0
> > [ 452.425069] device_unregister+0x16/0x60
> > [ 452.425070] device_destroy+0x3a/0x40
> > [ 452.425074] drm_dp_aux_unregister_devnode+0xea/0x180 [drm_kms_helper]
> > [ 452.425078] drm_dp_mst_topology_put_port+0x5b/0x110 [drm_kms_helper]
> > [ 452.425083] drm_dp_mst_topology_put_mstb+0xb6/0x180 [drm_kms_helper]
> > [ 452.425087] drm_dp_mst_topology_mgr_set_mst+0x233/0x2b0
> > [drm_kms_helper]
> > [ 452.425091] drm_dp_mst_topology_mgr_destroy+0x18/0xa0 [drm_kms_helper]
> > [ 452.425110] intel_dp_encoder_flush_work+0x32/0xb0 [i915]
> > [ 452.425128] intel_ddi_encoder_destroy+0x32/0x70 [i915]
> > [ 452.425137] drm_mode_config_cleanup+0x51/0x2e0 [drm]
> > [ 452.425157] intel_modeset_cleanup+0xc8/0x140 [i915]
> > [ 452.425168] i915_driver_unload+0xa8/0x130 [i915]
> > [ 452.425180] i915_pci_remove+0x1e/0x40 [i915]
> > [ 452.425182] pci_device_remove+0x3b/0xc0
> > [ 452.425183] device_release_driver_internal+0xe4/0x1d0
> > [ 452.425185] pci_stop_bus_device+0x69/0x90
> > [ 452.425186] pci_stop_and_remove_bus_device_locked+0x16/0x30
> > [ 452.425188] remove_store+0x75/0x90
> > [ 452.425189] kernfs_fop_write+0x116/0x190
> > [ 452.425191] vfs_write+0xa5/0x1a0
> > [ 452.425192] ksys_write+0x57/0xd0
> > [ 452.425194] do_syscall_64+0x55/0x150
> > [ 452.425195] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [ 452.425197] RIP: 0033:0x7f8cc1e7d038
> > [ 452.425198] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00
> > f3 0f 1e fa 48 8d 05 e5 76 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05
> > <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
> > [ 452.425199] RSP: 002b:00007ffce4321218 EFLAGS: 00000246 ORIG_RAX:
> > 0000000000000001
> > [ 452.425201] RAX: ffffffffffffffda RBX: 0000000000000002 RCX:
> > 00007f8cc1e7d038
> > [ 452.425202] RDX: 0000000000000002 RSI: 000056515aefbf00 RDI:
> > 0000000000000001
> > [ 452.425203] RBP: 000056515aefbf00 R08: 000000000000000a R09:
> > 00007f8cc1f0ee80
> > [ 452.425204] R10: 000000000000000a R11: 0000000000000246 R12:
> > 00007f8cc1f50780
> > [ 452.425205] R13: 0000000000000002 R14: 00007f8cc1f4b740 R15:
> > 0000000000000002
> > [ 452.425207] WARNING: CPU: 3 PID: 1887 at fs/sysfs/group.c:256
> > sysfs_remove_group+0x76/0x80
> > [ 452.425208] ---[ end trace a1c11eaf054910a5 ]---
> > [ 452.425282] [drm:drm_dp_aux_unregister_devnode [drm_kms_helper]]
> > drm_dp_aux_dev: aux [DPMST] unregistering
> > [ 452.425288] [drm:drm_dp_mst_topology_put_port [drm_kms_helper]] port
> > 000000002ba3174e (0)
> > [ 452.425292] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 000000002ba3174e (0)
> > [ 452.425295] [drm:drm_dp_mst_put_mstb_malloc [drm_kms_helper]] mstb
> > 00000000eec1a629 (2)
> > [ 452.425299] [drm:drm_dp_mst_put_mstb_malloc [drm_kms_helper]] mstb
> > 00000000eec1a629 (1)
> > [ 452.425311] [drm:drm_mode_object_put.part.3 [drm]] OBJ ID: 86 (1)
> > [ 452.425318] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000dde1b00a (1)
> > [ 452.425365] [drm:drm_dp_mst_put_port_malloc [drm_kms_helper]] port
> > 00000000dde1b00a (0)
> > [ 452.425368] [drm:drm_dp_mst_put_mstb_malloc [drm_kms_helper]] mstb
> > 00000000eec1a629 (0)
> >
> > So, we need to move the drm_dp_aux_register_devnode() call above the
> > connector
> > registration callback. Same goes for the port->aux.dev = port->connector-
> > > kdev; assignment that you do in patch 3/7 (and of course, you can remove
> > > the
> > connector registration status check there now).
> >
> > > +
> > > + drm_dp_aux_register_devnode(&port->aux);
> > > }
> > >
> > > out:
> > > @@ -1404,7 +1454,6 @@ static bool drm_dp_validate_guid(struct
> > > drm_dp_mst_topology_mgr *mgr,
> > > return false;
> > > }
> > >
> > > -#if 0
> > > static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8
> > > port_num,
> > > u32 offset, u8 num_bytes)
> > > {
> > > struct drm_dp_sideband_msg_req_body req;
> > > @@ -1417,7 +1466,6 @@ static int build_dpcd_read(struct
> > > drm_dp_sideband_msg_tx *msg, u8 port_num, u32
> > >
> > > return 0;
> > > }
> > > -#endif
> > >
> > > static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr
> > > *mgr,
> > > bool up, u8 *msg, int len)
> > > @@ -1994,26 +2042,55 @@ int drm_dp_update_payload_part2(struct
> > > drm_dp_mst_topology_mgr *mgr)
> > > }
> > > EXPORT_SYMBOL(drm_dp_update_payload_part2);
> > >
> > > -#if 0 /* unused as of yet */
> > > static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> > > struct drm_dp_mst_port *port,
> > > - int offset, int size)
> > > + int offset, int size, u8 *bytes)
> > > {
> > > int len;
> > > + int ret = 0;
> > > struct drm_dp_sideband_msg_tx *txmsg;
> > > + struct drm_dp_mst_branch *mstb;
> > > +
> > > + mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
> > > + if (!mstb)
> > > + return -EINVAL;
> > >
> > > txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> > > - if (!txmsg)
> > > - return -ENOMEM;
> > > + if (!txmsg) {
> > > + ret = -ENOMEM;
> > > + goto fail_put;
> > > + }
> > >
> > > - len = build_dpcd_read(txmsg, port->port_num, 0, 8);
> > > + len = build_dpcd_read(txmsg, port->port_num, offset, size);
> > > txmsg->dst = port->parent;
> > >
> > > drm_dp_queue_down_tx(mgr, txmsg);
> > >
> > > - return 0;
> > > + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> > > + if (ret < 0)
> > > + goto fail_free;
> > > +
> > > + /* DPCD read should never be NACKed */
> > > + if (WARN_ON_ONCE(txmsg->reply.reply_type == 1)) {
> > > + ret = -EIO;
> > > + goto fail_free;
> > > + }
> > > +
> > > + if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
> > > + ret = -EPROTO;
> > > + goto fail_free;
> > > + }
> > > +
> > > + ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
> > > size);
> > > + memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
> > > +
> > > +fail_free:
> > > + kfree(txmsg);
> > > +fail_put:
> > > + drm_dp_put_mst_branch_device(mstb);
> > > +
> > > + return ret;
> > > }
> > > -#endif
> > >
> > > static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
> > > struct drm_dp_mst_port *port,
> > > @@ -2041,9 +2118,9 @@ static int drm_dp_send_dpcd_write(struct
> > > drm_dp_mst_topology_mgr *mgr,
> > >
> > > ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> > > if (ret > 0) {
> > > - if (txmsg->reply.reply_type == 1) {
> > > - ret = -EINVAL;
> > > - } else
> > > + if (txmsg->reply.reply_type == 1)
> > > + ret = -EIO;
> > > + else
> > > ret = 0;
> > > }
> > > kfree(txmsg);
> > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> > > index 509667e..6dea76a 100644
> > > --- a/include/drm/drm_dp_helper.h
> > > +++ b/include/drm/drm_dp_helper.h
> > > @@ -1265,6 +1265,10 @@ struct drm_dp_aux {
> > > * @cec: struct containing fields used for CEC-Tunneling-over-
> > > AUX.
> > > */
> > > struct drm_dp_aux_cec cec;
> > > + /**
> > > + * @is_remote: Is this "AUX CH" actually using sideband messaging.
> > > + */
> > > + bool is_remote;
> > > };
> > >
> > > ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
> > > diff --git a/include/drm/drm_dp_mst_helper.h
> > > b/include/drm/drm_dp_mst_helper.h
> > > index 371cc28..30f8c11 100644
> > > --- a/include/drm/drm_dp_mst_helper.h
> > > +++ b/include/drm/drm_dp_mst_helper.h
> > > @@ -615,6 +615,12 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
> > >
> > > void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr
> > > *mgr);
> > > int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr
> > > *mgr);
> > > +
> > > +ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
> > > + unsigned int offset, void *buffer, size_t
> > > size);
> > > +ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
> > > + unsigned int offset, void *buffer, size_t
> > > size);
> > > +
> > > struct drm_dp_mst_topology_state
> > > *drm_atomic_get_mst_topology_state(struct
> > > drm_atomic_state *state,
> > > struc
> > > t
> > > drm_dp_mst_topology_mgr *mgr);
> > > int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> > --
> > Cheers,
> > Lyude Paul
> >
--
Cheers,
Lyude Paul
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