From: Jani Nikula jani.nikula@intel.com
[ Upstream commit 79c901c93562bdf1c84ce6c1b744fbbe4389a6eb ]
For development and testing purposes, the i915.force_probe module parameter and DRM_I915_FORCE_PROBE kconfig option allow probing of devices that aren't supported by the driver.
The i915.force_probe module parameter is "unsafe" and setting it taints the kernel. However, using the kconfig option does not.
Always taint the kernel when force probing a device that is not supported.
v2: Drop "depends on EXPERT" to avoid build breakage (kernel test robot)
Fixes: 7ef5ef5cdead ("drm/i915: add force_probe module parameter to replace alpha_support") Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@linux.intel.com Cc: Daniel Vetter daniel@ffwll.ch Cc: Dave Airlie airlied@gmail.com Acked-by: Daniel Vetter daniel.vetter@ffwll.ch Reviewed-by: Rodrigo Vivi rodrigo.vivi@intel.com Signed-off-by: Jani Nikula jani.nikula@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20230504103508.1818540-1-jani.... (cherry picked from commit 3312bb4ad09ca6423bd4a5b15a94588a8962fb8e) Signed-off-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/i915/Kconfig | 12 +++++++----- drivers/gpu/drm/i915/i915_pci.c | 6 ++++++ 2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig index 98f4e44976e09..9c9bb0a0dcfca 100644 --- a/drivers/gpu/drm/i915/Kconfig +++ b/drivers/gpu/drm/i915/Kconfig @@ -62,10 +62,11 @@ config DRM_I915_FORCE_PROBE This is the default value for the i915.force_probe module parameter. Using the module parameter overrides this option.
- 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. + Force probe the i915 driver for Intel graphics devices that are + recognized but not properly supported by this kernel version. Force + probing an unsupported device taints the kernel. 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. @@ -75,7 +76,8 @@ config DRM_I915_FORCE_PROBE 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 "*" to force probe the driver for all known devices. Not + recommended.
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 diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 125f7ef1252c3..2b5aaea422208 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -1346,6 +1346,12 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) return -ENODEV; }
+ if (intel_info->require_force_probe) { + dev_info(&pdev->dev, "Force probing unsupported Device ID %04x, tainting kernel\n", + pdev->device); + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + } + /* 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