From: "Leo (Sunpeng) Li" <sunpeng.li@amd.com>
Date: Tue, 6 Feb 2018 10:20:46 -0500
Subject: drm/amd/display: Skip 2 frames when first reading CRC
Git-commit: a0a31ec4ce6a8c8bc4f4b8619b537e4a9a0ddaf1
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
Skipping the first frame will prevent uncoooked values most of the time.
However, in some unlikely cases, the second frame will be uncooked as
well.
Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 2 +-
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c | 12 ++++++------
2 files changed, 7 insertions(+), 7 deletions(-)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -198,7 +198,7 @@ struct dm_crtc_state {
struct drm_crtc_state base;
struct dc_stream_state *stream;
- bool crc_first_skipped;
+ int crc_skip_count;
bool crc_enabled;
};
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
@@ -84,8 +84,8 @@ int amdgpu_dm_crtc_set_crc_source(struct
}
*values_cnt = 3;
- /* Reset crc_skipped flag on dm state */
- crtc_state->crc_first_skipped = false;
+ /* Reset crc_skipped on dm state */
+ crtc_state->crc_skip_count = 0;
return 0;
}
@@ -109,11 +109,11 @@ void amdgpu_dm_crtc_handle_crc_irq(struc
/*
* Since flipping and crc enablement happen asynchronously, we - more
* often than not - will be returning an 'uncooked' crc on first frame.
- * Probably because hw isn't ready yet. Simply skip the first crc
- * value.
+ * Probably because hw isn't ready yet. For added security, skip the
+ * first two CRC values.
*/
- if (!crtc_state->crc_first_skipped) {
- crtc_state->crc_first_skipped = true;
+ if (crtc_state->crc_skip_count < 2) {
+ crtc_state->crc_skip_count += 1;
return;
}