On 28/04/2025 06:21, Shengyu Qu wrote:
Hi,
Personally I prefer we always disable cursor HW degamma, and this is
what color pipeline patch series have done for cursor plane(actually
all colorops are disabled on cursor plane and its background plane).
Since cursor plane shares colorops with cursor's background plane.
Hi Shengyu,
This feature isn't related to under-discussion plane color mgmt, neither
the current atomic CRTC color properties, where this cursor degamma is
always disable. It's only needed for DRM legacy gamma because of the
implict sRGB done by AMD display driver for this property.
Best Regards,
Melissa
Also, degamma a sRGB image with sRGB curve is not a good choice, or we
have to fake screen TRC to sRGB curve while the screen actually is
calibrated to power 2.2 curve.
Best regards,
Shengyu
在 2025/4/22 22:58, Melissa Wen 写道:
This reverts commit 272e6aab14bbf98d7a06b2b1cd6308a02d4a10a1.
Applying degamma curve to the cursor by default breaks Linux userspace
expectation.
On Linux, AMD display manager enables cursor degamma ROM just for
implict sRGB on HW versions where degamma is split into two blocks:
degamma ROM for pre-defined TFs and `gamma correction` for user/custom
curves, and degamma ROM settings doesn't apply to cursor plane.
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1513
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2803
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4144
Reported-by: Michel Dänzer <michel.daen...@mailbox.org>
Signed-off-by: Melissa Wen <m...@igalia.com>
---
Hi,
I suspect there is a conflict of interest between OSes here, because
this is not the first time this mechanism has been removed from the
DC shared-code and after reintroduced [1].
I'd suggest that other OSes set the `dc_cursor_attributes
attribute_flags.bits.ENABLE_CURSOR_DEGAMMA` to true by default, rather
than removing the mechanism that is valid for the Linux driver. Similar
to what the Linux AMD DM does for the implicit sRGB [2][3], but in their
case, they just need to initialize with 1.
Finally, thanks Michel for pointing this issue out to me and noticing
the similarity to previous solution.
[1] https://gitlab.freedesktop.org/agd5f/linux/-/commit/d9fbd64e8e317
[2] https://gitlab.freedesktop.org/agd5f/linux/-/commit/857b835f
[3] https://gitlab.freedesktop.org/agd5f/linux/-/commit/66eba12a
Best Regards,
Melissa
drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp_cm.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git
a/drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp_cm.c
b/drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp_cm.c
index 1236e0f9a256..712aff7e17f7 100644
--- a/drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp_cm.c
+++ b/drivers/gpu/drm/amd/display/dc/dpp/dcn401/dcn401_dpp_cm.c
@@ -120,10 +120,11 @@ void dpp401_set_cursor_attributes(
enum dc_cursor_color_format color_format =
cursor_attributes->color_format;
int cur_rom_en = 0;
- // DCN4 should always do Cursor degamma for Cursor Color modes
if (color_format == CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA ||
color_format == CURSOR_MODE_COLOR_UN_PRE_MULTIPLIED_ALPHA) {
- cur_rom_en = 1;
+ if
(cursor_attributes->attribute_flags.bits.ENABLE_CURSOR_DEGAMMA) {
+ cur_rom_en = 1;
+ }
}
REG_UPDATE_3(CURSOR0_CONTROL,
