drm/i915/adl_p: Allow underrun recovery when possible
ADL_P requires that we disable underrun recovery when downscaling (or
using the scaler for YUV420 pipe output), using DSC, or using PSR2.
Otherwise we should be able to enable the underrun recovery.
On DG2 we need to keep underrun recovery disabled at all times, but the
chicken bit in PIPE_CHICKEN has an inverted meaning (it's an enable bit
instead of disable).
v2:
- Reverse the condition (clear the disable bit when supported, set
disable bit when not supported).
Bspec: 50351
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727145056.2049720-1-matthew.d.roper@intel.com
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e4d0ad7..730afa3 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8393,7 +8393,8 @@ enum {
#define _PIPEC_CHICKEN 0x72038
#define PIPE_CHICKEN(pipe) _MMIO_PIPE(pipe, _PIPEA_CHICKEN,\
_PIPEB_CHICKEN)
-#define UNDERRUN_RECOVERY_DISABLE REG_BIT(30)
+#define UNDERRUN_RECOVERY_DISABLE_ADLP REG_BIT(30)
+#define UNDERRUN_RECOVERY_ENABLE_DG2 REG_BIT(30)
#define PIXEL_ROUNDING_TRUNC_FB_PASSTHRU (1 << 15)
#define PER_PIXEL_ALPHA_BYPASS_EN (1 << 7)
