From: Jani Nikula Date: Thu, 4 May 2023 10:35:08 +0000 (+0300) Subject: drm/i915: taint kernel when force probing unsupported devices X-Git-Tag: v6.6.7~2855^2~1^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=79c901c93562bdf1c84ce6c1b744fbbe4389a6eb;p=platform%2Fkernel%2Flinux-starfive.git drm/i915: taint kernel when force probing unsupported devices 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 Cc: Rodrigo Vivi Cc: Tvrtko Ursulin Cc: Daniel Vetter Cc: Dave Airlie Acked-by: Daniel Vetter Reviewed-by: Rodrigo Vivi Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20230504103508.1818540-1-jani.nikula@intel.com (cherry picked from commit 3312bb4ad09ca6423bd4a5b15a94588a8962fb8e) Signed-off-by: Joonas Lahtinen --- diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig index 06a0ca1..e4f4d2e 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 "[,,...]" 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 2a012da..edcfb5f 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -1344,6 +1344,12 @@ 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