From: Greg KH <gregkh@linuxfoundation.org>
To: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org, dkk089@gmail.com, jani.nikula@intel.com,
mika.kahola@intel.com
Subject: Re: [PATCH stable-4.20] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
Date: Wed, 13 Feb 2019 15:52:19 +0100 [thread overview]
Message-ID: <20190213145219.GA19166@kroah.com> (raw)
In-Reply-To: <20190213144734.1344-1-ville.syrjala@linux.intel.com>
On Wed, Feb 13, 2019 at 04:47:34PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> 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@vger.kernel.org # v4.20+
> Cc: Daniel Kamil Kozar <dkk089@gmail.com>
> Reported-by: Daniel Kamil Kozar <dkk089@gmail.com>
> Tested-by: Daniel Kamil Kozar <dkk089@gmail.com>
> 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@linux.intel.com>
> Link: https://patchwork.freedesktop.org/patch/msgid/20190111174950.10681-1-ville.syrjala@linux.intel.com
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>
> (cherry picked from commit 7bed8adcd9f86231bb69bbc02f88ad89330f99e3)
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> Link: https://patchwork.freedesktop.org/patch/msgid/20190205141846.6053-1-ville.syrjala@linux.intel.com
> (cherry picked from commit d028a646e84b9b131e4ff2cb5bbdd3825d141028)
Now queued up, thanks.
greg k-h
prev parent reply other threads:[~2019-02-13 14:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 13:54 FAILED: patch "[PATCH] drm/i915: Try to sanitize bogus DPLL state left over by" failed to apply to 4.20-stable tree gregkh
2019-02-13 14:47 ` [PATCH stable-4.20] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen Ville Syrjala
2019-02-13 14:52 ` Greg KH [this message]
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