drm/i915: re-disable RC6p on Sandy Bridge

RC6p on Sandy Bridge got re-enabled over time, causing visual glitches
and GPU hangs.

Disabled originally in commit 1c8ecf80fdee ("drm/i915: do not enable
RC6p on Sandy Bridge").

Signed-off-by: Sasa Dragic <sasa.dragic@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219172927.9603-2-sasa.dragic@gmail.com
Fixes: fb6db0f5bf1d ("drm/i915: Remove unsafe i915.enable_rc6")
Fixes: 13c5a577b342 ("drm/i915/gt: Select the deepest available parking mode for rc6")
Cc: stable@vger.kernel.org
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 46acbf39019553ff1043a7631abea84c93194c3a..be700413199ed1a1ed6c1b46b0005dedd6d9cab0 100644 (file)
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -423,7 +423,8 @@ static const struct intel_device_info ilk_m_info = {
        .has_coherent_ggtt = true, \
        .has_llc = 1, \
        .has_rc6 = 1, \
-       .has_rc6p = 1, \
+       /* snb does support rc6p, but enabling it causes various issues */ \
+       .has_rc6p = 0, \
        .has_rps = true, \
        .dma_mask_size = 40, \
        .__runtime.ppgtt_type = INTEL_PPGTT_ALIASING, \