[PATCH] drm/probe_helper: sort out poll_running vs poll_enabled
Jani Nikula
jani.nikula at linux.intel.com
Fri Jan 13 09:47:22 UTC 2023
On Fri, 13 Jan 2023, Dmitry Baryshkov <dmitry.baryshkov at linaro.org> wrote:
> On Fri, 13 Jan 2023 at 09:12, Laurentiu Palcu
> <laurentiu.palcu at oss.nxp.com> wrote:
>>
>> Hi Dmitry,
>>
>> On Thu, Jan 12, 2023 at 05:42:47PM +0200, Dmitry Baryshkov wrote:
>> > There are two flags attemting to guard connector polling:
>> > poll_enabled and poll_running. While poll_enabled semantics is clearly
>> > defined and fully adhered (mark that drm_kms_helper_poll_init() was
>> > called and not finalized by the _fini() call), the poll_running flag
>> > doesn't have such clearliness.
>> >
>> > This flag is used only in drm_helper_probe_single_connector_modes() to
>> > guard calling of drm_kms_helper_poll_enable, it doesn't guard the
>> > drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
>> > is actually running. Tie HPD enablement to this flag.
>> >
>> > This fix the following warning reported after merging the HPD series:
>>
>> s/fix/fixes/
>>
>> >
>> > Hot plug detection already enabled
>> > WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 drm_bridge_hpd_enable+0x94/0x9c [drm]
>> > Modules linked in: videobuf2_memops snd_soc_simple_card snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common snd_soc_imx_spdif adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
>> > CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
>> > Hardware name: NXP i.MX8MQ EVK (DT)
>> > Workqueue: events_unbound deferred_probe_work_func
>> > pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>> > pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
>> > lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
>> > sp : ffff800009ef3740
>> > x29: ffff800009ef3740 x28: ffff000009331f00 x27: 0000000000001000
>> > x26: 0000000000000020 x25: ffff800001148ed8 x24: ffff00000a8fe000
>> > x23: 00000000fffffffd x22: ffff000005086348 x21: ffff800001133ee0
>> > x20: ffff00000550d800 x19: ffff000005086288 x18: 0000000000000006
>> > x17: 0000000000000000 x16: ffff8000096ef008 x15: 97ffff2891004260
>> > x14: 2a1403e194000000 x13: 97ffff2891004260 x12: 2a1403e194000000
>> > x11: 7100385f29400801 x10: 0000000000000aa0 x9 : ffff800008112744
>> > x8 : ffff000000250b00 x7 : 0000000000000003 x6 : 0000000000000011
>> > x5 : 0000000000000000 x4 : ffff0000bd986a48 x3 : 0000000000000001
>> > x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000250000
>> > Call trace:
>> > drm_bridge_hpd_enable+0x94/0x9c [drm]
>> > drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
>> > drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
>> > drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
>> > drm_client_modeset_probe+0x204/0x1190 [drm]
>> > __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
>> > drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
>> > drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
>> > drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
>> > dcss_kms_attach+0x1c8/0x254 [imx_dcss]
>> > dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
>> > platform_probe+0x70/0xcc
>> > really_probe+0xc4/0x2e0
>> > __driver_probe_device+0x80/0xf0
>> > driver_probe_device+0xe0/0x164
>> > __device_attach_driver+0xc0/0x13c
>> > bus_for_each_drv+0x84/0xe0
>> > __device_attach+0xa4/0x1a0
>> > device_initial_probe+0x1c/0x30
>> > bus_probe_device+0xa4/0xb0
>> > deferred_probe_work_func+0x90/0xd0
>> > process_one_work+0x200/0x474
>> > worker_thread+0x74/0x43c
>> > kthread+0xfc/0x110
>> > ret_from_fork+0x10/0x20
>> > ---[ end trace 0000000000000000 ]---
>> >
>> > Reported-by: Laurentiu Palcu <laurentiu.palcu at oss.nxp.com>
>> > Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
>> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>> > ---
>> > drivers/gpu/drm/drm_probe_helper.c | 110 +++++++++++++++++------------
>> > 1 file changed, 63 insertions(+), 47 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
>> > index 7973f2589ced..ef919d95fea6 100644
>> > --- a/drivers/gpu/drm/drm_probe_helper.c
>> > +++ b/drivers/gpu/drm/drm_probe_helper.c
>> > @@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
>> > return ret;
>> > }
>> >
>> > +static void drm_kms_helper_disable_hpd(struct drm_device *dev)
>> > +{
>> > + struct drm_connector *connector;
>> > + struct drm_connector_list_iter conn_iter;
>> > +
>> > + drm_connector_list_iter_begin(dev, &conn_iter);
>> > + drm_for_each_connector_iter(connector, &conn_iter) {
>> > + const struct drm_connector_helper_funcs *funcs =
>> > + connector->helper_private;
>> > +
>> > + if (funcs && funcs->disable_hpd)
>> > + funcs->disable_hpd(connector);
>> > + }
>> > + drm_connector_list_iter_end(&conn_iter);
>> > +}
>> > +
>> > +static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
>> > +{
>> > + bool poll = false;
>> > + struct drm_connector *connector;
>> > + struct drm_connector_list_iter conn_iter;
>> > +
>> > + drm_connector_list_iter_begin(dev, &conn_iter);
>> > + drm_for_each_connector_iter(connector, &conn_iter) {
>> > + const struct drm_connector_helper_funcs *funcs =
>> > + connector->helper_private;
>> > +
>> > + if (funcs && funcs->disable_hpd)
>> > + funcs->disable_hpd(connector);
>>
>> I believe this is not right. You probably wanted to use enable_hpd
>> instead of disable_hpd on these two lines? Otherwise HPD would not work
>> at all.
>
> Argh. Too many refactorings. I'll check that it works correctly and
> respin.
Please Cc: intel-gfx at lists.freedesktop.org on the respin to run this on
our CI.
Thanks,
Jani.
>
>>
>> Thanks,
>> Laurentiu
>>
>> > +
>> > + if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
>> > + DRM_CONNECTOR_POLL_DISCONNECT))
>> > + poll = true;
>> > + }
>> > + drm_connector_list_iter_end(&conn_iter);
>> > +
>> > + return poll;
>> > +}
>> > +
>> > #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
>> > /**
>> > * drm_kms_helper_poll_enable - re-enable output polling.
>> > @@ -241,26 +280,14 @@ drm_connector_mode_valid(struct drm_connector *connector,
>> > void drm_kms_helper_poll_enable(struct drm_device *dev)
>> > {
>> > bool poll = false;
>> > - struct drm_connector *connector;
>> > - struct drm_connector_list_iter conn_iter;
>> > unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
>> >
>> > - if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
>> > + if (!dev->mode_config.poll_enabled ||
>> > + !drm_kms_helper_poll ||
>> > + dev->mode_config.poll_running)
>> > return;
>> >
>> > - drm_connector_list_iter_begin(dev, &conn_iter);
>> > - drm_for_each_connector_iter(connector, &conn_iter) {
>> > - const struct drm_connector_helper_funcs *funcs =
>> > - connector->helper_private;
>> > -
>> > - if (funcs && funcs->enable_hpd)
>> > - funcs->enable_hpd(connector);
>> > -
>> > - if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
>> > - DRM_CONNECTOR_POLL_DISCONNECT))
>> > - poll = true;
>> > - }
>> > - drm_connector_list_iter_end(&conn_iter);
>> > + poll = drm_kms_helper_enable_hpd(dev);
>> >
>> > if (dev->mode_config.delayed_event) {
>> > /*
>> > @@ -279,6 +306,8 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>> >
>> > if (poll)
>> > schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
>> > +
>> > + dev->mode_config.poll_running = true;
>> > }
>> > EXPORT_SYMBOL(drm_kms_helper_poll_enable);
>> >
>> > @@ -567,10 +596,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>> > }
>> >
>> > /* Re-enable polling in case the global poll config changed. */
>> > - if (drm_kms_helper_poll != dev->mode_config.poll_running)
>> > - drm_kms_helper_poll_enable(dev);
>> > -
>> > - dev->mode_config.poll_running = drm_kms_helper_poll;
>> > + drm_kms_helper_poll_enable(dev);
>> >
>> > if (connector->status == connector_status_disconnected) {
>> > DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
>> > @@ -710,8 +736,12 @@ static void output_poll_execute(struct work_struct *work)
>> > changed = dev->mode_config.delayed_event;
>> > dev->mode_config.delayed_event = false;
>> >
>> > - if (!drm_kms_helper_poll)
>> > + if (!drm_kms_helper_poll &&
>> > + dev->mode_config.poll_running) {
>> > + drm_kms_helper_disable_hpd(dev);
>> > + dev->mode_config.poll_running = false;
>> > goto out;
>> > + }
>> >
>> > if (!mutex_trylock(&dev->mode_config.mutex)) {
>> > repoll = true;
>> > @@ -808,30 +838,6 @@ bool drm_kms_helper_is_poll_worker(void)
>> > }
>> > EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
>> >
>> > -static void drm_kms_helper_poll_disable_fini(struct drm_device *dev, bool fini)
>> > -{
>> > - struct drm_connector *connector;
>> > - struct drm_connector_list_iter conn_iter;
>> > -
>> > - if (!dev->mode_config.poll_enabled)
>> > - return;
>> > -
>> > - if (fini)
>> > - dev->mode_config.poll_enabled = false;
>> > -
>> > - drm_connector_list_iter_begin(dev, &conn_iter);
>> > - drm_for_each_connector_iter(connector, &conn_iter) {
>> > - const struct drm_connector_helper_funcs *funcs =
>> > - connector->helper_private;
>> > -
>> > - if (funcs && funcs->disable_hpd)
>> > - funcs->disable_hpd(connector);
>> > - }
>> > - drm_connector_list_iter_end(&conn_iter);
>> > -
>> > - cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
>> > -}
>> > -
>> > /**
>> > * drm_kms_helper_poll_disable - disable output polling
>> > * @dev: drm_device
>> > @@ -848,7 +854,12 @@ static void drm_kms_helper_poll_disable_fini(struct drm_device *dev, bool fini)
>> > */
>> > void drm_kms_helper_poll_disable(struct drm_device *dev)
>> > {
>> > - drm_kms_helper_poll_disable_fini(dev, false);
>> > + if (dev->mode_config.poll_running)
>> > + drm_kms_helper_disable_hpd(dev);
>> > +
>> > + cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
>> > +
>> > + dev->mode_config.poll_running = false;
>> > }
>> > EXPORT_SYMBOL(drm_kms_helper_poll_disable);
>> >
>> > @@ -886,7 +897,12 @@ EXPORT_SYMBOL(drm_kms_helper_poll_init);
>> > */
>> > void drm_kms_helper_poll_fini(struct drm_device *dev)
>> > {
>> > - drm_kms_helper_poll_disable_fini(dev, true);
>> > + if (!dev->mode_config.poll_enabled)
>> > + return;
>> > +
>> > + drm_kms_helper_poll_disable(dev);
>> > +
>> > + dev->mode_config.poll_enabled = false;
>> > }
>> > EXPORT_SYMBOL(drm_kms_helper_poll_fini);
>> >
>> > --
>> > 2.39.0
>> >
--
Jani Nikula, Intel Open Source Graphics Center
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