[Intel-gfx] [PATCH] drm/i915: Expand force_probe to block probe of devices as well.
Rodrigo Vivi
rodrigo.vivi at intel.com
Fri Dec 30 17:08:44 UTC 2022
On Fri, Dec 30, 2022 at 02:42:51PM +0200, Jani Nikula wrote:
> On Fri, 30 Dec 2022, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> > On Thu, Dec 29, 2022 at 03:01:34PM -0300, Gustavo Sousa wrote:
> >> On Thu, Dec 29, 2022 at 11:12:30AM -0500, Rodrigo Vivi wrote:
> >> > There are new cases where we want to block i915 probe, such
> >> > as when experimenting or developing the new Xe driver.
> >> >
> >> > But also, with the new hibrid cards, users or developers might
> >> > want to use i915 only on integrated and fully block the probe
> >> > of the i915 for the discrete. Or vice versa.
> >> >
> >> > Oh, and there are even older development and validation reasons,
> >> > like when you use some distro where the modprobe.blacklist is
> >> > not present.
> >> >
> >> > But in any case, let's introduce a more granular control, but without
> >> > introducing yet another parameter, but using the existent force_probe
> >> > one.
> >> >
> >> > Just by adding a ! in the begin of the id in the force_probe, like
> >> > in this case where we would block the probe for Alder Lake:
> >> >
> >> > $ insmod i915.ko force_probe='!46a6'
> >> >
> >> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> >> > ---
> >> > drivers/gpu/drm/i915/Kconfig | 13 ++++++++++---
> >> > drivers/gpu/drm/i915/i915_params.c | 2 +-
> >> > drivers/gpu/drm/i915/i915_pci.c | 29 +++++++++++++++++++++++++----
> >> > 3 files changed, 36 insertions(+), 8 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> >> > index 3efce05d7b57..8873cd0355b7 100644
> >> > --- a/drivers/gpu/drm/i915/Kconfig
> >> > +++ b/drivers/gpu/drm/i915/Kconfig
> >> > @@ -54,24 +54,31 @@ config DRM_I915
> >> > If "M" is selected, the module will be called i915.
> >> >
> >> > config DRM_I915_FORCE_PROBE
> >> > - string "Force probe driver for selected new Intel hardware"
> >> > + string "Force probe i915 for selected Intel hardware IDs"
> >> > depends on DRM_I915
> >> > help
> >> > This is the default value for the i915.force_probe module
> >> > parameter. Using the module parameter overrides this option.
> >> >
> >> > - Force probe the driver for new Intel graphics devices that are
> >> > + Force probe the i915 for Intel graphics devices that are
> >> > recognized but not properly supported by this kernel version. It is
> >> > recommended to upgrade to a kernel version with proper support as soon
> >> > as it is available.
> >> >
> >> > + It can also be used to block the probe of recognized and fully
> >> > + supported devices.
> >> > +
> >> > Use "" to disable force probe. If in doubt, use this.
> >> >
> >> > - Use "<pci-id>[,<pci-id>,...]" to force probe the driver for listed
> >> > + Use "<pci-id>[,<pci-id>,...]" to force probe the i915 for listed
> >> > devices. For example, "4500" or "4500,4571".
> >> >
> >> > Use "*" to force probe the driver for all known devices.
> >> >
> >> > + Use "!" right before the ID to block the probe of the device. For
> >> > + example, "4500,!4571" forces the probe of 4500 and blocks the probe of
> >> > + 4571.
> >> > +
> >> > config DRM_I915_CAPTURE_ERROR
> >> > bool "Enable capturing GPU state following a hang"
> >> > depends on DRM_I915
> >> > diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> >> > index 61578f2860cd..d634bd3f641a 100644
> >> > --- a/drivers/gpu/drm/i915/i915_params.c
> >> > +++ b/drivers/gpu/drm/i915/i915_params.c
> >> > @@ -122,7 +122,7 @@ i915_param_named_unsafe(enable_psr2_sel_fetch, bool, 0400,
> >> > "Default: 0");
> >> >
> >> > i915_param_named_unsafe(force_probe, charp, 0400,
> >> > - "Force probe the driver for specified devices. "
> >> > + "Force probe options for specified supported devices. "
> >> > "See CONFIG_DRM_I915_FORCE_PROBE for details.");
> >> >
> >> > i915_param_named_unsafe(disable_power_well, int, 0400,
> >> > diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> >> > index 668e9da52584..fc1383f3a646 100644
> >> > --- a/drivers/gpu/drm/i915/i915_pci.c
> >> > +++ b/drivers/gpu/drm/i915/i915_pci.c
> >> > @@ -1253,7 +1253,7 @@ static void i915_pci_remove(struct pci_dev *pdev)
> >> > }
> >> >
> >> > /* is device_id present in comma separated list of ids */
> >> > -static bool force_probe(u16 device_id, const char *devices)
> >> > +static bool device_id_in_list(u16 device_id, const char *devices, bool negative)
> >> > {
> >> > char *s, *p, *tok;
> >> > bool ret;
> >> > @@ -1272,6 +1272,12 @@ static bool force_probe(u16 device_id, const char *devices)
> >> > for (p = s, ret = false; (tok = strsep(&p, ",")) != NULL; ) {
> >> > u16 val;
> >> >
> >> > + if (negative && tok[0] == '!')
> >> > + tok++;
> >> > + else if ((negative && tok[0] != '!') ||
> >> > + (!negative && tok[0] == '!'))
> >> > + continue;
> >> > +
> >> > if (kstrtou16(tok, 16, &val) == 0 && val == device_id) {
> >> > ret = true;
> >> > break;
> >> > @@ -1283,6 +1289,16 @@ static bool force_probe(u16 device_id, const char *devices)
> >> > return ret;
> >> > }
> >> >
> >> > +static bool id_forced(u16 device_id)
> >> > +{
> >> > + return device_id_in_list(device_id, i915_modparams.force_probe, false);
> >> > +}
> >> > +
> >> > +static bool id_blocked(u16 device_id)
> >> > +{
> >> > + return device_id_in_list(device_id, i915_modparams.force_probe, true);
> >> > +}
> >>
> >> I think id_blocked() would return true for any device id if force_probe was "*".
> >
> > good catch. I will just wait until middle next week to see if someone has something
> > against the idea in general and then re-spin a version with:
> >
> > - if (strcmp(devices, "*") == 0)
> > + if (strcmp(devices, "*") == 0 && !negative)
>
> I admit I didn't bother checking, but please ensure force_probe=!* also
> works to block everything.
makes sense
- if (strcmp(devices, "*") == 0)
+ if (negative && strcmp(devices, "!*") == 0)
+ return true;
+ if (!negative && strcmp(devices, "*") == 0)
will be it.
Thanks,
Rodrigo.
>
> BR,
> Jani.
>
> >
> >>
> >> > +
> >> > bool i915_pci_resource_valid(struct pci_dev *pdev, int bar)
> >> > {
> >> > if (!pci_resource_flags(pdev, bar))
> >> > @@ -1308,10 +1324,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> >> > (struct intel_device_info *) ent->driver_data;
> >> > int err;
> >> >
> >> > - if (intel_info->require_force_probe &&
> >> > - !force_probe(pdev->device, i915_modparams.force_probe)) {
> >> > + if (intel_info->require_force_probe && !id_forced(pdev->device)) {
> >> > dev_info(&pdev->dev,
> >> > - "Your graphics device %04x is not properly supported by the driver in this\n"
> >> > + "Your graphics device %04x is not properly supported by i915 in this\n"
> >> > "kernel version. To force driver probe anyway, use i915.force_probe=%04x\n"
> >> > "module parameter or CONFIG_DRM_I915_FORCE_PROBE=%04x configuration option,\n"
> >> > "or (recommended) check for kernel updates.\n",
> >> > @@ -1319,6 +1334,12 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> >> > return -ENODEV;
> >> > }
> >> >
> >> > + if (id_blocked(pdev->device)) {
> >> > + dev_info(&pdev->dev, "I915 probe blocked for Device ID %04x.\n",
> >> > + pdev->device);
> >> > + return -ENODEV;
> >> > + }
> >> > +
> >> > /* Only bind to function 0 of the device. Early generations
> >> > * used function 1 as a placeholder for multi-head. This causes
> >> > * us confusion instead, especially on the systems where both
> >> > --
> >> > 2.38.1
> >> >
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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