On Wed, Feb 13, 2019 at 04:47:34PM +0200, Ville Syrjala wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Certain SNB machines (eg. ASUS K53SV) seem to have a broken BIOS > which misprograms the hardware badly when encountering a suitably > high resolution display. The programmed pipe timings are somewhat > bonkers and the DPLL is totally misprogrammed (P divider == 0). > That will result in atomic commit timeouts as apparently the pipe > is sufficiently stuck to not signal vblank interrupts. > > IIRC something like this was also observed on some other SNB > machine years ago (might have been a Dell XPS 8300) but a BIOS > update cured it. Sadly looks like this was never fixed for the > ASUS K53SV as the latest BIOS (K53SV.320 11/11/2011) is still > broken. > > The quickest way to deal with this seems to be to shut down > the pipe+ports+DPLL. Unfortunately doing this during the > normal sanitization phase isn't quite soon enough as we > already spew several WARNs about the bogus hardware state. > But it's better than hanging the boot for a few dozen seconds. > Since this is limited to a few old machines it doesn't seem > entirely worthwile to try and rework the readout+sanitization > code to handle it more gracefully. > > v2: Fix potential NULL deref (kbuild test robot) > Constify has_bogus_dpll_config() > > Cc: stable@xxxxxxxxxxxxxxx # v4.20+ > Cc: Daniel Kamil Kozar <dkk089@xxxxxxxxx> > Reported-by: Daniel Kamil Kozar <dkk089@xxxxxxxxx> > Tested-by: Daniel Kamil Kozar <dkk089@xxxxxxxxx> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109245 > Fixes: 516a49cc1946 ("drm/i915: Fix assert_plane() warning on bootup with external display") > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Link: https://patchwork.freedesktop.org/patch/msgid/20190111174950.10681-1-ville.syrjala@xxxxxxxxxxxxxxx > Reviewed-by: Mika Kahola <mika.kahola@xxxxxxxxx> > (cherry picked from commit 7bed8adcd9f86231bb69bbc02f88ad89330f99e3) > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> > Link: https://patchwork.freedesktop.org/patch/msgid/20190205141846.6053-1-ville.syrjala@xxxxxxxxxxxxxxx > (cherry picked from commit d028a646e84b9b131e4ff2cb5bbdd3825d141028) Now queued up, thanks. greg k-h
