This is a note to let you know that I've just added the patch titled
drm/edid: add a quirk for two LG monitors to get them to work on 10bpc
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-edid-add-a-quirk-for-two-lg-monitors-to-get-them.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b1df0fa6739e2c13bc519d6ca152c518c6da5c60
Author: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Date: Fri Oct 21 16:37:34 2022 -0400
drm/edid: add a quirk for two LG monitors to get them to work on 10bpc
[ Upstream commit aa193f7eff8ff753577351140b8af13b76cdc7c2 ]
The LG 27GP950 and LG 27GN950 have visible display corruption when
trying to use 10bpc modes. So, to fix this, cap their maximum DSC
target bitrate to 15bpp.
Suggested-by: Roman Li <roman.li@xxxxxxx>
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index eaa819381281..fefcfac999d9 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -87,6 +87,8 @@ static int oui(u8 first, u8 second, u8 third)
#define EDID_QUIRK_FORCE_10BPC (1 << 11)
/* Non desktop display (i.e. HMD) */
#define EDID_QUIRK_NON_DESKTOP (1 << 12)
+/* Cap the DSC target bitrate to 15bpp */
+#define EDID_QUIRK_CAP_DSC_15BPP (1 << 13)
#define MICROSOFT_IEEE_OUI 0xca125c
@@ -147,6 +149,12 @@ static const struct edid_quirk {
EDID_QUIRK('F', 'C', 'M', 13600, EDID_QUIRK_PREFER_LARGE_75 |
EDID_QUIRK_DETAILED_IN_CM),
+ /* LG 27GP950 */
+ EDID_QUIRK('G', 'S', 'M', 0x5bbf, EDID_QUIRK_CAP_DSC_15BPP),
+
+ /* LG 27GN950 */
+ EDID_QUIRK('G', 'S', 'M', 0x5b9a, EDID_QUIRK_CAP_DSC_15BPP),
+
/* LGD panel of HP zBook 17 G2, eDP 10 bpc, but reports unknown bpc */
EDID_QUIRK('L', 'G', 'D', 764, EDID_QUIRK_FORCE_10BPC),
@@ -6116,6 +6124,7 @@ static void drm_reset_display_info(struct drm_connector *connector)
info->mso_stream_count = 0;
info->mso_pixel_overlap = 0;
+ info->max_dsc_bpp = 0;
}
static u32 update_display_info(struct drm_connector *connector,
@@ -6202,6 +6211,9 @@ static u32 update_display_info(struct drm_connector *connector,
info->non_desktop = true;
}
+ if (quirks & EDID_QUIRK_CAP_DSC_15BPP)
+ info->max_dsc_bpp = 15;
+
return quirks;
}
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 7df7876b2ad5..d9879fc9ceb1 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -635,6 +635,12 @@ struct drm_display_info {
* @mso_pixel_overlap: eDP MSO segment pixel overlap, 0-8 pixels.
*/
u8 mso_pixel_overlap;
+
+ /**
+ * @max_dsc_bpp: Maximum DSC target bitrate, if it is set to 0 the
+ * monitor's default value is used instead.
+ */
+ u32 max_dsc_bpp;
};
int drm_display_info_set_bus_formats(struct drm_display_info *info,
