On Tue, Aug 19, 2019, Ville Syrjälä wrote: >On Tue, Aug 06, 2019 at 07:30:21PM +0800, Lee Shawn C wrote: >> Refer to EDID 1.3 spec, display FEATURE (byte 18h) bit #0 said >> "If this bit is set to 1, the display supports timings based on the >> GTF standard using default GTF parameter values". >> >> And EDID 1.4 spec shows "If bit 0 is set to 0, then the display >> is noncontinuous frequency (multi-mode) and is only specified to accept >> the video timing formats that are listed in BASE EDID and certain >> EXTENSION Blocks. >> >> When display feature did not support CVT or GFT2 and monitor's EDID version >> greater than or equal to "1.2". DRM driver would select GTF as default >> for standard timing calculation. It may generated some video timing >> that can't display properly by external monitor. >> >> For example. When driver retrieved "0xD1 0xFC" (FHD, 120Hz) and >> "0xD1 0xE8" (FHD, 100Hz) from "Standard Timings". GTF formula >> would generate video timing like below. It already over monitor's >> spec to cause black screen issue. >> "1920x1080" 120 368881 1920 2072 2288 2656 1080 1081 1084 1157 0x0 0x6 >> "1920x1080" 100 301992 1920 2072 2280 2640 1080 1081 1084 1144 0x0 0x6 >> >> Cc: Jani Nikula <jani.nikula@xxxxxxxxx> >> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> >> Cc: Adam Jackson <ajax@xxxxxxxxxx> >> Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx> >> Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx> >> --- >> drivers/gpu/drm/drm_edid.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c >> index 82a4ceed3fcf..f6a3d2d993c7 100644 >> --- a/drivers/gpu/drm/drm_edid.c >> +++ b/drivers/gpu/drm/drm_edid.c >> @@ -2089,7 +2089,9 @@ static int standard_timing_level(struct edid *edid) >> return LEVEL_CVT; >> if (drm_gtf2_hbreak(edid)) >> return LEVEL_GTF2; >> - return LEVEL_GTF; >> + if (edid->revision == 3 && (edid->features & DRM_EDID_FEATURE_DEFAULT_GTF)) >> + return LEVEL_GTF; > >While the oldest EDID spec I have is 1.3, sources on the interwebs >suggest that older revisions already had the "default GTF" flag here. >So I think we can omit the revision check. > I'm sorry I miss this comment and already push pathc v2. Thanks! >> + >> } >> return LEVEL_DMT; >> } >> -- >> 2.17.1 >> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
