On Tue, 05 Feb 2019, Ville Syrjala <ville.syrj...@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrj...@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: sta...@vger.kernel.org # v4.20+
> Cc: Daniel Kamil Kozar <dkk...@gmail.com>
> Reported-by: Daniel Kamil Kozar <dkk...@gmail.com>
> Tested-by: Daniel Kamil Kozar <dkk...@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.syrj...@linux.intel.com>
> Link:
> https://patchwork.freedesktop.org/patch/msgid/20190111174950.10681-1-ville.syrj...@linux.intel.com
> Reviewed-by: Mika Kahola <mika.kah...@intel.com>
> (cherry picked from commit 7bed8adcd9f86231bb69bbc02f88ad89330f99e3)
Pushed to drm-intel-fixes, thanks.
BR,
Jani.
> ---
> drivers/gpu/drm/i915/intel_display.c | 50 ++++++++++++++++++++++++----
> 1 file changed, 44 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index 3da9c0f9e948..248128126422 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15415,16 +15415,45 @@ static void intel_sanitize_crtc(struct intel_crtc
> *crtc,
> }
> }
>
> +static bool has_bogus_dpll_config(const struct intel_crtc_state *crtc_state)
> +{
> + struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
> +
> + /*
> + * Some SNB BIOSen (eg. ASUS K53SV) are known to misprogram
> + * the hardware when a high res displays plugged in. DPLL P
> + * divider is zero, and the pipe timings are bonkers. We'll
> + * try to disable everything in that case.
> + *
> + * FIXME would be nice to be able to sanitize this state
> + * without several WARNs, but for now let's take the easy
> + * road.
> + */
> + return IS_GEN6(dev_priv) &&
> + crtc_state->base.active &&
> + crtc_state->shared_dpll &&
> + crtc_state->port_clock == 0;
> +}
> +
> static void intel_sanitize_encoder(struct intel_encoder *encoder)
> {
> struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> struct intel_connector *connector;
> + struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
> + struct intel_crtc_state *crtc_state = crtc ?
> + to_intel_crtc_state(crtc->base.state) : NULL;
>
> /* We need to check both for a crtc link (meaning that the
> * encoder is active and trying to read from a pipe) and the
> * pipe itself being active. */
> - bool has_active_crtc = encoder->base.crtc &&
> - to_intel_crtc(encoder->base.crtc)->active;
> + bool has_active_crtc = crtc_state &&
> + crtc_state->base.active;
> +
> + if (crtc_state && has_bogus_dpll_config(crtc_state)) {
> + DRM_DEBUG_KMS("BIOS has misprogrammed the hardware. Disabling
> pipe %c\n",
> + pipe_name(crtc->pipe));
> + has_active_crtc = false;
> + }
>
> connector = intel_encoder_find_connector(encoder);
> if (connector && !has_active_crtc) {
> @@ -15435,16 +15464,25 @@ static void intel_sanitize_encoder(struct
> intel_encoder *encoder)
> /* Connector is active, but has no active pipe. This is
> * fallout from our resume register restoring. Disable
> * the encoder manually again. */
> - if (encoder->base.crtc) {
> - struct drm_crtc_state *crtc_state =
> encoder->base.crtc->state;
> + if (crtc_state) {
> + struct drm_encoder *best_encoder;
>
> DRM_DEBUG_KMS("[ENCODER:%d:%s] manually disabled\n",
> encoder->base.base.id,
> encoder->base.name);
> +
> + /* avoid oopsing in case the hooks consult best_encoder
> */
> + best_encoder = connector->base.state->best_encoder;
> + connector->base.state->best_encoder = &encoder->base;
> +
> if (encoder->disable)
> - encoder->disable(encoder,
> to_intel_crtc_state(crtc_state), connector->base.state);
> + encoder->disable(encoder, crtc_state,
> + connector->base.state);
> if (encoder->post_disable)
> - encoder->post_disable(encoder,
> to_intel_crtc_state(crtc_state), connector->base.state);
> + encoder->post_disable(encoder, crtc_state,
> + connector->base.state);
> +
> + connector->base.state->best_encoder = best_encoder;
> }
> encoder->base.crtc = NULL;
--
Jani Nikula, Intel Open Source Graphics Center
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