Hi Harry, Alex, The solution given while reviewing my patch was that "DC should support enabling a CRTC without a framebuffer." Since the revert is a temporary workaround to address issue at hand and considering the bigger regression it will cause on ChromeOS(explained below), I would strongly recommend that the revert should not be mainlined (to linus tree), until a proper fix for both the issues i.e., flickering and BUG hit on atomic is found. For the sake of everyone's understanding in the list below is a brief background. Mainline patch from intel folks, "846c7df drm/atomic: Try to preserve the crtc enabled state in drm_atomic_remove_fb, v2." introduces a slight behavioral change to rmfb. Instead of disabling a crtc when the primary plane is disabled, it now preserves it. This change leads to BUG hit while performing atomic commit on amd driver leading to reboot/system instability on ChromeOS which has enabled drm atomic way of rendering, I also remember it causing some issue on other OS as well. Thanks & Regards, Shirish S -----Original Message----- From: Michel Dänzer [mailto:michel@xxxxxxxxxxx] Sent: Thursday, April 12, 2018 8:39 PM To: Wentland, Harry <Harry.Wentland at amd.com> Cc: amd-gfx at lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher at amd.com>; S, Shirish <Shirish.S at amd.com> Subject: Re: [PATCH 2/2] Revert "drm/amd/display: disable CRTCs with NULL FB on their primary plane (V2)" On 2018-04-12 04:51 PM, Harry Wentland wrote: > This seems to cause flickering and lock-ups for a wide range of users. > Revert until we've found a proper fix for the flickering and lock-ups. > > This reverts commit 36cc549d59864b7161f0e23d710c1c4d1b9cf022. > > Cc: Shirish S <shirish.s at amd.com> > Cc: Alex Deucher <alexander.deucher at amd.com> > Cc: stable at vger.kernel.org > Signed-off-by: Harry Wentland <harry.wentland at amd.com> Thanks Harry, both patches are Reviewed-by: Michel Dänzer <michel.daenzer at amd.com> -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
