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author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-08-04 08:43:53 +0100 |
---|---|---|
committer | Chris Wilson <chris@chris-wilson.co.uk> | 2016-08-04 10:28:05 +0100 |
commit | 36dbc4d76918d7557b686f807106dcc799174b12 (patch) | |
tree | 275ce92daef1bb730d114e2d7adebd5ba7e8c0dd /drivers | |
parent | 5ac9793bf9f43cb4d8ecdcc521be1ba87057841a (diff) | |
download | linux-36dbc4d76918d7557b686f807106dcc799174b12.tar.bz2 |
drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
"Display flickering may occur when both FBC (Frame Buffer Compression)
and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
and in use by the display controller."
Ville found the w/a name in the database:
WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt and also dug out that it
affects Broxton.
v2: Log when the quirk is applied.
v3: Ensure i915.enable_fbc is false when !HAS_FBC()
v4: Fix function name after rebase
v5: Add Broxton to the workaround
Note for backporting to stable, we need to add
#define mkwrite_device_info(ptr) \
((struct intel_device_info *)INTEL_INFO(ptr))
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://patchwork.freedesktop.org/patch/msgid/1470296633-20388-1-git-send-email-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/gpu/drm/i915/intel_fbc.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c index 8147eb9e8475..d4be07615aa9 100644 --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -1229,12 +1229,29 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv) if (i915.enable_fbc >= 0) return !!i915.enable_fbc; + if (!HAS_FBC(dev_priv)) + return 0; + if (IS_BROADWELL(dev_priv)) return 1; return 0; } +static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv) +{ +#ifdef CONFIG_INTEL_IOMMU + /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */ + if (intel_iommu_gfx_mapped && + (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))) { + DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n"); + return true; + } +#endif + + return false; +} + /** * intel_fbc_init - Initialize FBC * @dev_priv: the i915 device @@ -1252,6 +1269,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv) fbc->active = false; fbc->work.scheduled = false; + if (need_fbc_vtd_wa(dev_priv)) + mkwrite_device_info(dev_priv)->has_fbc = false; + i915.enable_fbc = intel_sanitize_fbc_option(dev_priv); DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc); |