3.3-stable review patch. If anyone has any objections, please let me know.
------------------ From: Chris Wilson <[email protected]> commit f47166d2b0001fcb752b40c5a2d4db986dfbea68 upstream. Quoting the BSpec from time immemorial: PIPEACONF, bits 28:27: Frame Start Delay (Debug) Used to delay the frame start signal that is sent to the display planes. Care must be taken to insure that there are enough lines during VBLANK to support this setting. An instance of the BIOS leaving these bits set was found in the wild, where it caused our modesetting to go all squiffy and skewiff. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47271 Reported-and-tested-by: Eva Wang <[email protected]> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43012 Reported-and-tested-by: Carl Richell <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Signed-off-by: Daniel Vetter <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_display.c | 6 ++++++ 2 files changed, 7 insertions(+) --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2313,6 +2313,7 @@ #define PIPECONF_DISABLE 0 #define PIPECONF_DOUBLE_WIDE (1<<30) #define I965_PIPECONF_ACTIVE (1<<30) +#define PIPECONF_FRAME_START_DELAY_MASK (3<<27) #define PIPECONF_SINGLE_WIDE 0 #define PIPECONF_PIPE_UNLOCKED 0 #define PIPECONF_PIPE_LOCKED (1<<25) --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7497,6 +7497,12 @@ static void intel_sanitize_modesetting(s struct drm_i915_private *dev_priv = dev->dev_private; u32 reg, val; + /* Clear any frame start delays used for debugging left by the BIOS */ + for_each_pipe(pipe) { + reg = PIPECONF(pipe); + I915_WRITE(reg, I915_READ(reg) & ~PIPECONF_FRAME_START_DELAY_MASK); + } + if (HAS_PCH_SPLIT(dev)) return; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
