Re: kernel error with drm

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sat, 8 Dec 2018 17:38:05 +0000
    From:        Arthur Barlow <arthurbarlow%gmail.com@localhost>
    Message-ID:  <CANR6Wa5u22CLN+8ecnmVyXH9wZnm3invc=ka5ji6tfNZJRJCNQ%mail.gmail.com@localhost>

  | I have noticed periodically that I get and error in my xconsole that reads:
  | kern error: [drm:(/usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_sprite.c:132)intel_pipe_update_start] *ERROR* Potential atomic update failure on pipe A: -35

I see this as well, from time to time.   It doesn't seem to affect anything.

I do get occasional graphics glitches, most often in seamonkey, or
vncviewer) but they clear up on any redraw ... as best I can tell the
two are unrelated.

My dmesg.boot file, which collected messages from before the last boot
(which was after a USB related crash of some kind ... it happens occasionally
when I connect my android phone, purely to charge it -- all I see when
that happens is the firmware reboot screen - I do not have DDB enabled,
no idea if it is software or some kind of hardware/power glitch)
also contains this message:

[ 1600733.2718263] kern error: [drm:(/readonly/release/testing/src/sys/external/
bsd/drm2/dist/drm/i915/intel_sprite.c:205)intel_pipe_update_end] *ERROR* Atomic 
update failure on pipe A (start=55041453 end=55041454) time 5 us, min 1073, max 
1079, scanline start 1078, end 1080

Again, I was unaware of that at the time, so it had no serious detectable 
effects.


  | The processor is an Intel Core2 P8600 with Intel graphics, (G45).

Mine is:
cpu0: "Intel(R) Core(TM) i5-7300HQ CPU @ 2.50GHz"
cpu0: Intel 7th gen Core (Kaby Lake) (686-class), 2496.49 MHz

and the kernel identifies the graphics as:

i915drmkms0 at pci0 dev 2 function 0: Intel HD Graphics 630 (GT2, Mobile) (rev. 0x04)

I'm using the X server that was in 8.99.whatever-it-was in late January.
and a much more recent (8.99.25) kernel (mid November) - the error
(or the error message anyway) has been there since Kaby Lake support
appeared (don't recall if it was there when the system was using vesa
fallback, but I'd expect probably not).

kre