Messages in this thread | | | From | "Deucher, Alexander" <> | Subject | RE: Linux 3.8-rc4 | Date | Wed, 30 Jan 2013 15:53:58 +0000 |
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> -----Original Message----- > From: Shuah Khan [mailto:shuahkhan@gmail.com] > Sent: Wednesday, January 30, 2013 10:35 AM > To: Deucher, Alexander > Cc: Linus Torvalds; Linux Kernel Mailing List > Subject: Re: Linux 3.8-rc4 > > On Wed, Jan 30, 2013 at 6:31 AM, Deucher, Alexander > <Alexander.Deucher@amd.com> wrote: > > >> > >> ok. I did more debugging in rv515_mc_stop() and here is what's > >> happening. It has two display controllers and one of them is enabled > >> and the other is in disabled state when AVIVO_D1CRTC_CONTROL is > >> checked. The current code doesn't blank the disabled crtc. However, it > >> needs to be blanked to avoid DMAR faults it appears. I think that is > >> what the original code prior to > >> 6253e4c75d96006c06b9ac8f417eba873de2497b commit was doing: > >> > >> - WREG32(R_0060E8_D1CRTC_UPDATE_LOCK, 1); > >> - WREG32(R_0068E8_D2CRTC_UPDATE_LOCK, 1); > >> - WREG32(R_006080_D1CRTC_CONTROL, 0); > >> - WREG32(R_006880_D2CRTC_CONTROL, 0); > >> - WREG32(R_0060E8_D1CRTC_UPDATE_LOCK, 0); > >> - WREG32(R_0068E8_D2CRTC_UPDATE_LOCK, 0); > >> - WREG32(R_000330_D1VGA_CONTROL, 0); > >> - WREG32(R_000338_D2VGA_CONTROL, 0); > >> > >> Anyways, here is the diff for the change (by no means a patch) I made > >> that fixed the problem: > > > > Unfortunately, that just fixes the problem by causing an additional delay > since the wait_for_vblank() and get_frame_count() loops will timeout since > the secondary display is disabled. The previous code disabled the displays > completely while the new code just disables the memory request interface > so that the display timing stays on to avoid additional flicker at startup or GPU > reset. For some reason on your system there seems to be a delay in getting > the memory request interface to stop. > > > > Alex > > Right. That makes sense and yes the annoying flicker went away. :) Can > you think of something that can address systems that would need more > time to get the memory request interface to stop such as mine?
Does adding an additional radeon_mc_wait_for_idle(rdev) call at the end of rv515_mc_stop() help? Can you find out what the minimum delay required for your system is?
Alex
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