diff options
author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2015-04-10 18:21:28 +0300 |
---|---|---|
committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-05-08 15:56:30 +0200 |
commit | 70722468872b0752abaff54d34ed16af0d95cb9f (patch) | |
tree | 4bae993705263b9fee73148ffc79db22bfe41a47 /drivers/gpu/drm/i915/i915_reg.h | |
parent | 2e523e98bb593950de2c749d4ceb45cc20313c1a (diff) |
drm/i915: Work around DISPLAY_PHY_CONTROL register corruption on CHV
Sometimes (exactly when is a bit unclear) DISPLAY_PHY_CONTROL appears to
get corrupted. The values I've managed to read from it seem to have some
pattern but vary quite a lot. The corruption doesn't seem to just happen
when the register is accessed, but can also happen spontaneosly during
modeset. When this happens during a modeset things go south and the
display doesn't light up.
I've managed to hit the problemn when toggling HDMI on port D on and
off. When things get corrupted the display doesn't light up, but as soon
as I manually write the correct value to the register the display comes
up.
First I was suspicious that we ourselves accidentally overwrite it with
garbage, but didn't catch anything with the reg_rw tracepoint. Also I
sprinkled check all over the modeset path to see exactly when the
corruption happens, and eg. the read back value was fine just before
intel_dp_set_m(), and corrupted immediately after it. I also made my
check function repair the register value whenever it was wrong, and with
this approach the corruption repeated several times during the modeset
operation, always seeming to trigger in the same exact calls to the
check function, while other calls to the function never caught anything.
So far I've not seen this problem occurring when carefully avoiding all
read accesses to DISPLAY_PHY_CONTROL. Not sure if that's just pure luck
or an actual workaround, but we can hope it works. So let's avoid reading
the register and instead track the desired value of the register in dev_priv.
v2: Read out the power well state to determine initial register value
v3: Use DPIO_CHx names instead of raw numbers
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_reg.h')
-rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 98f10810bdbd..58627a319416 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2137,7 +2137,10 @@ enum skl_disp_power_wells { #define DPIO_PHY_STATUS (VLV_DISPLAY_BASE + 0x6240) #define DPLL_PORTD_READY_MASK (0xf) #define DISPLAY_PHY_CONTROL (VLV_DISPLAY_BASE + 0x60100) -#define PHY_COM_LANE_RESET_DEASSERT(phy) (1 << (phy)) +#define PHY_CH_SU_PSR 0x1 +#define PHY_CH_DEEP_PSR 0x7 +#define PHY_CH_POWER_MODE(mode, phy, ch) ((mode) << (6*(phy)+3*(ch)+2)) +#define PHY_COM_LANE_RESET_DEASSERT(phy) (1 << (phy)) #define DISPLAY_PHY_STATUS (VLV_DISPLAY_BASE + 0x60104) #define PHY_POWERGOOD(phy) (((phy) == DPIO_PHY0) ? (1<<31) : (1<<30)) |