Bug 109141
| Summary: | 12bpc hdmi causes wrong real refresh rate (swapbuffers return time) | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Kevin Mitchell (kevmitch) |
| Component: | Video(DRI - Intel) | Assignee: | intel-gfx-bugs (intel-gfx-bugs) |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | intel-gfx-bugs, kevmitch |
| Priority: | P1 | ||
| Hardware: | Intel | ||
| OS: | Linux | ||
| Kernel Version: | 4.3 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
Samsung un40eh5000 edid reported by xrandr --prop
above edid decoded by edid-decode |
||
Created attachment 196931 [details]
above edid decoded by edid-decode
Please file new i915 bugs at the freedesktop.org bugzilla https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel so by "new bugs" you mean I should *not* re-report this there? |
Created attachment 196911 [details] Samsung un40eh5000 edid reported by xrandr --prop I have a Samsung un40eh5000 tv that I connect to my Ivy Bridge Lenovo T530 laptop via mini display-port to hdmi. I have attached the raw and decoded EDID. As of 7a0baa6234468aa387f9b8a1a79dc2a4b4821f67, it seems 12bpc gets enabled on this setup (though I can't imagine that my machine or my TV actually support that in real life). Unfortunately, this seems to change the effective refresh rate as measured between returns from opengl swapbuffers calls for example in glxgears. | glxgears fps | +----------------+ xrandr | before | after | -------+--------+-------+ 23.98 | 24.00 | 23.85 | 24.00 | 24.00 | 24.13 | 29.97 | 30.00 | 29.81 | 30.00 | 30.00 | 30.17 | 59.94 | 60.00 | 60.12 | 60.00 | 60.00 | 60.12 | This is problematic for displaying video at native frame rates. For example when the actual refresh rate of 24.00 hz could be achieved, 23.98fps video would only have to repeat a frame every 50 seconds. Now it must either drop or repeat one every 7 seconds which is much more noticeable.