Re: port-amd64/55023: pixelation under X

[Leonardo Taccari <leot%NetBSD.org@localhost>]

The following reply was made to PR port-amd64/55023; it has been noted by GNATS.

From: Leonardo Taccari <leot%NetBSD.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-amd64/55023: pixelation under X
Date: Wed, 26 Feb 2020 17:57:09 +0100

 Hello Roy,
 
 rcbixler%nyx.net@localhost writes:
 > [...]
 > >Description:
 > Using a browser under X, I sometimes see pixelation or distortion when scrolling.  I sometimes also see this when entering text into the URL bar.  If I wait long enough, it goes away.  I first saw this problem under NetBSD-9 and still see it under the current stable version.  The problem did not occur under NetBSD-8 or 8.1.  The hardware is a Lenovo Thinkpad X1 Carbon.
 >
 > When booting, I see a couple of errors:
 >
 > [     8.683492] kern info: [drm] Memory usable by graphics device = 2048M
 > [     8.683492] kern info: [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
 > [     8.683492] kern info: [drm] Driver supports precise vblank timestamp query.
 > [     8.683492] kern info: [drm] failed to find VBIOS tables
 > [     8.683492] i915drmkms0: interrupting at ioapic0 pin 16 (i915drmkms0)
 > [     8.783570] kern info: [drm] GMBUS [i915 gmbus vga] timed out, falling back to bit banging on pin 2
 > [     8.903664] kern info: [drm] GMBUS [i915 gmbus dpb] timed out, falling back to bit banging on pin 5
 > [     8.963710] intelfb0 at i915drmkms0
 > [     8.963710] intelfb0: framebuffer at 0xffffc48063d2a000, size 1600x900, depth 32, stride 6400
 > [     9.223915] kern error: [drm:(/usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_fifo_underrun.c:230)cpt_set_fifo_underrun_reporting] *ERROR* uncleared pch fifo underrun on pch transcoder A
 > [     9.223915] kern error: [drm:(/usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_fifo_underrun.c:381)intel_pch_fifo_underrun_irq_handler] *ERROR* PCH transcoder A FIFO underrun
 > [...]
 
 Can you please share the exact model of the video card and/or the
 /var/log/Xorg.0.log?
 
 (Here - on NetBSD/amd64 -current - I have with an Intel(R) HD Graphics
 4400 and an Intel(R) HD Graphics 4600 I use the `SNA' "AccelMethod" in
 /etc/X11/xorg.conf and `INTEL_DRIVER_DATE= 2014' in mk.conf.  With the
 no INTEL_DRIVER_DATE (latest intel driver) if I use the SNA
 acceleration I see what you have described above while `UXA'
 "AccelMethod" seems to work well.)