On Wed, 2016-08-31 at 21:51 +0000, Zanoni, Paulo R wrote: > Hi > > Em Qua, 2016-08-31 às 14:43 -0700, James Bottomley escreveu: > > On Wed, 2016-08-31 at 11:23 -0700, James Bottomley wrote: > > > > > > On Fri, 2016-08-26 at 09:10 -0400, James Bottomley wrote: > > > > > > > > We seem to have an xrandr regression with skylake now. What's > > > > happening is that I can get output on to a projector, but the > > > > system is losing video when I change the xrandr sessions (like > > > > going from a --above b to a --same-as b). The main screen goes > > > > blank, which is basically a reboot situation. Unfortunately, I > > > > can't seem to get the logs out of systemd to see if there was a > > > > dump to dmesg (the system was definitely responding). > > > > > > > > I fell back to 4.6.2 which worked perfectly, so this is > > > > definitely > > > > some sort of regression. I'll be able to debug more fully when > > > > I > > > > get back home from the Linux Security Summit. > > > > > > I'm home now. Unfortunately, my monitor isn't as problematic as > > > the > > > projector, but by flipping between various modes and separating > > > and > > > overlaying the panels with --above and --same-as (xrandr), I can > > > eventually get it to the point where the main LCD panel goes > > > black > > > and can only be restarted by specifying a different mode. > > > > > > This seems to be associated with these lines in the X > > > > > > [ 14714.389] (EE) intel(0): failed to set mode: Invalid argument > > > [22] > > > > > > But the curious thing is that even if this fails with the error > > > message once, it may succeed a second time, so it looks to be a > > > transient error translation problem from the kernel driver. > > > > > > I've attached the full log below. > > > > > > This is only with a VGA output. I currently don't have a HDMI > > > dongle, but I'm in the process of acquiring one. > > > > After more playing around, I'm getting thousands of these in the > > kernel > > log (possibly millions: the log wraps very fast): > > > > [23504.873606] [drm:intel_dp_start_link_train [i915]] *ERROR* > > failed > > to train DP, aborting > > > > And then finally it gives up with > > > > [25023.770951] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] > > *ERROR* CPU pipe B FIFO underrun > > [25561.926075] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] > > *ERROR* CPU pipe A FIFO underrun > > > > And the crtc for the VGA output becomes non-responsive to any > > configuration command. This requires a reboot and sometimes a UEFI > > variable reset before it comes back. > > Please see this discussion: > https://patchwork.freedesktop.org/patch/103237/ > > Do you have this patch on your tree? Does the problem go away if you > revert it? Yes, I've got it, it went in in 4.8-rc3 according to git: commit 58e311b09c319183254d9220c50a533e7157c9ab Author: Matt Roper <matthew.d.roper@xxxxxxxxx> Date: Thu Aug 4 14:08:00 2016 -0700 drm/i915/gen9: Give one extra block per line for SKL plane WM calculations Reverting it causes the secondary display not to sync pretty much at all. However, in the flickers I can see, it does work OK and doesn't now crash switching from --same-as to --above and back I also still get the logs filling up with the link training errors. On balance, although the behaviour is different, it's not an improvement because if I can't sync with the projector, I can't really use this as a fix. James _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
