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* [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
@ 2019-01-09 12:09 Ville Syrjala
  2019-01-10 19:41 ` [Intel-gfx] " kbuild test robot
  2019-01-11 17:49 ` [PATCH v2] " Ville Syrjala
  0 siblings, 2 replies; 5+ messages in thread
From: Ville Syrjala @ 2019-01-09 12:09 UTC (permalink / raw)
  To: intel-gfx; +Cc: stable, Daniel Kamil Kozar

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.

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>
---
 drivers/gpu/drm/i915/intel_display.c | 51 ++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 696e6f5680df..ea2e09d36b4d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15435,16 +15435,46 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc,
 	}
 }
 
+static bool has_bogus_dpll_config(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_GEN(dev_priv, 6) &&
+		crtc_state &&
+		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 (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) {
@@ -15455,16 +15485,25 @@ 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;
 
-- 
2.19.2


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [Intel-gfx] [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
  2019-01-09 12:09 [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen Ville Syrjala
@ 2019-01-10 19:41 ` " kbuild test robot
  2019-01-11 17:49 ` [PATCH v2] " Ville Syrjala
  1 sibling, 0 replies; 5+ messages in thread
From: kbuild test robot @ 2019-01-10 19:41 UTC (permalink / raw)
  To: kbuild, Ville Syrjala
  Cc: Dan Carpenter, kbuild-all, intel-gfx, Daniel Kamil Kozar, stable

Hi Ville,

Thank you for the patch! Perhaps something to improve:

url:    https://github.com/0day-ci/linux/commits/Ville-Syrjala/drm-i915-Try-to-sanitize-bogus-DPLL-state-left-over-by-broken-SNB-BIOSen/20190109-222838
base:   git://anongit.freedesktop.org/drm-intel for-linux-next

New smatch warnings:
drivers/gpu/drm/i915/intel_display.c:15452 has_bogus_dpll_config() warn: variable dereferenced before check 'crtc_state' (see line 15439)
drivers/gpu/drm/i915/intel_display.c:15472 intel_sanitize_encoder() error: we previously assumed 'crtc_state' could be null (see line 15469)
drivers/gpu/drm/i915/intel_display.c:15487 intel_sanitize_encoder() warn: variable dereferenced before check 'crtc_state' (see line 15472)

# https://github.com/0day-ci/linux/commit/5a0056f774727561e522ccde5fe7fe78d343d25f
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 5a0056f774727561e522ccde5fe7fe78d343d25f
vim +/crtc_state +15452 drivers/gpu/drm/i915/intel_display.c

249293524 Daniel Vetter     2012-07-02  15436  
5a0056f77 Ville Syrjälä     2019-01-09  15437  static bool has_bogus_dpll_config(struct intel_crtc_state *crtc_state)
5a0056f77 Ville Syrjälä     2019-01-09  15438  {
5a0056f77 Ville Syrjälä     2019-01-09 @15439  	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
5a0056f77 Ville Syrjälä     2019-01-09  15440  
5a0056f77 Ville Syrjälä     2019-01-09  15441  	/*
5a0056f77 Ville Syrjälä     2019-01-09  15442  	 * Some SNB BIOSen (eg. ASUS K53SV) are known to misprogram
5a0056f77 Ville Syrjälä     2019-01-09  15443  	 * the hardware when a high res displays plugged in. DPLL P
5a0056f77 Ville Syrjälä     2019-01-09  15444  	 * divider is zero, and the pipe timings are bonkers. We'll
5a0056f77 Ville Syrjälä     2019-01-09  15445  	 * try to disable everything in that case.
5a0056f77 Ville Syrjälä     2019-01-09  15446  	 *
5a0056f77 Ville Syrjälä     2019-01-09  15447  	 * FIXME would be nice to be able to sanitize this state
5a0056f77 Ville Syrjälä     2019-01-09  15448  	 * without several WARNs, but for now let's take the easy
5a0056f77 Ville Syrjälä     2019-01-09  15449  	 * road.
5a0056f77 Ville Syrjälä     2019-01-09  15450  	 */
5a0056f77 Ville Syrjälä     2019-01-09  15451  	return IS_GEN(dev_priv, 6) &&
5a0056f77 Ville Syrjälä     2019-01-09 @15452  		crtc_state &&
5a0056f77 Ville Syrjälä     2019-01-09  15453  		crtc_state->base.active &&
5a0056f77 Ville Syrjälä     2019-01-09  15454  		crtc_state->shared_dpll &&
5a0056f77 Ville Syrjälä     2019-01-09  15455  		crtc_state->port_clock == 0;
5a0056f77 Ville Syrjälä     2019-01-09  15456  }
5a0056f77 Ville Syrjälä     2019-01-09  15457  
249293524 Daniel Vetter     2012-07-02  15458  static void intel_sanitize_encoder(struct intel_encoder *encoder)
249293524 Daniel Vetter     2012-07-02  15459  {
70332ac53 Imre Deak         2018-11-01  15460  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
249293524 Daniel Vetter     2012-07-02  15461  	struct intel_connector *connector;
5a0056f77 Ville Syrjälä     2019-01-09  15462  	struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
5a0056f77 Ville Syrjälä     2019-01-09  15463  	struct intel_crtc_state *crtc_state = crtc ?
5a0056f77 Ville Syrjälä     2019-01-09  15464  		to_intel_crtc_state(crtc->base.state) : NULL;
249293524 Daniel Vetter     2012-07-02  15465  
249293524 Daniel Vetter     2012-07-02  15466  	/* We need to check both for a crtc link (meaning that the
249293524 Daniel Vetter     2012-07-02  15467  	 * encoder is active and trying to read from a pipe) and the
249293524 Daniel Vetter     2012-07-02  15468  	 * pipe itself being active. */
5a0056f77 Ville Syrjälä     2019-01-09 @15469  	bool has_active_crtc = crtc_state &&
5a0056f77 Ville Syrjälä     2019-01-09  15470  		crtc_state->base.active;
5a0056f77 Ville Syrjälä     2019-01-09  15471  
5a0056f77 Ville Syrjälä     2019-01-09 @15472  	if (has_bogus_dpll_config(crtc_state)) {
5a0056f77 Ville Syrjälä     2019-01-09  15473  		DRM_DEBUG_KMS("BIOS has misprogrammed the hardware. Disabling pipe %c\n",
5a0056f77 Ville Syrjälä     2019-01-09  15474  			      pipe_name(crtc->pipe));
5a0056f77 Ville Syrjälä     2019-01-09  15475  		has_active_crtc = false;
5a0056f77 Ville Syrjälä     2019-01-09  15476  	}
249293524 Daniel Vetter     2012-07-02  15477  
496b0fc37 Maarten Lankhorst 2016-08-23  15478  	connector = intel_encoder_find_connector(encoder);
496b0fc37 Maarten Lankhorst 2016-08-23  15479  	if (connector && !has_active_crtc) {
249293524 Daniel Vetter     2012-07-02  15480  		DRM_DEBUG_KMS("[ENCODER:%d:%s] has active connectors but no active pipe!\n",
249293524 Daniel Vetter     2012-07-02  15481  			      encoder->base.base.id,
8e329a039 Jani Nikula       2014-06-03  15482  			      encoder->base.name);
249293524 Daniel Vetter     2012-07-02  15483  
249293524 Daniel Vetter     2012-07-02  15484  		/* Connector is active, but has no active pipe. This is
249293524 Daniel Vetter     2012-07-02  15485  		 * fallout from our resume register restoring. Disable
249293524 Daniel Vetter     2012-07-02  15486  		 * the encoder manually again. */
5a0056f77 Ville Syrjälä     2019-01-09 @15487  		if (crtc_state) {
5a0056f77 Ville Syrjälä     2019-01-09  15488  			struct drm_encoder *best_encoder;
fd6bbda9c Maarten Lankhorst 2016-08-09  15489  
249293524 Daniel Vetter     2012-07-02  15490  			DRM_DEBUG_KMS("[ENCODER:%d:%s] manually disabled\n",
249293524 Daniel Vetter     2012-07-02  15491  				      encoder->base.base.id,
8e329a039 Jani Nikula       2014-06-03  15492  				      encoder->base.name);
5a0056f77 Ville Syrjälä     2019-01-09  15493  
5a0056f77 Ville Syrjälä     2019-01-09  15494  			/* avoid oopsing in case the hooks consult best_encoder */
5a0056f77 Ville Syrjälä     2019-01-09  15495  			best_encoder = connector->base.state->best_encoder;
5a0056f77 Ville Syrjälä     2019-01-09  15496  			connector->base.state->best_encoder = &encoder->base;
5a0056f77 Ville Syrjälä     2019-01-09  15497  
c84c6fe30 Jani Nikula       2018-10-16  15498  			if (encoder->disable)
5a0056f77 Ville Syrjälä     2019-01-09  15499  				encoder->disable(encoder, crtc_state,
5a0056f77 Ville Syrjälä     2019-01-09  15500  						 connector->base.state);
a62d14975 Ville Syrjälä     2014-06-28  15501  			if (encoder->post_disable)
5a0056f77 Ville Syrjälä     2019-01-09  15502  				encoder->post_disable(encoder, crtc_state,
5a0056f77 Ville Syrjälä     2019-01-09  15503  						      connector->base.state);
5a0056f77 Ville Syrjälä     2019-01-09  15504  
5a0056f77 Ville Syrjälä     2019-01-09  15505  			connector->base.state->best_encoder = best_encoder;
249293524 Daniel Vetter     2012-07-02  15506  		}
7f1950fbb Egbert Eich       2014-04-25  15507  		encoder->base.crtc = NULL;
249293524 Daniel Vetter     2012-07-02  15508  
249293524 Daniel Vetter     2012-07-02  15509  		/* Inconsistent output/port/pipe state happens presumably due to
249293524 Daniel Vetter     2012-07-02  15510  		 * a bug in one of the get_hw_state functions. Or someplace else
249293524 Daniel Vetter     2012-07-02  15511  		 * in our code, like the register restore mess on resume. Clamp
249293524 Daniel Vetter     2012-07-02  15512  		 * things to off as a safer default. */
fd6bbda9c Maarten Lankhorst 2016-08-09  15513  
7f1950fbb Egbert Eich       2014-04-25  15514  		connector->base.dpms = DRM_MODE_DPMS_OFF;
7f1950fbb Egbert Eich       2014-04-25  15515  		connector->base.encoder = NULL;
249293524 Daniel Vetter     2012-07-02  15516  	}
d6cae4aa3 Maarten Lankhorst 2018-05-16  15517  
d6cae4aa3 Maarten Lankhorst 2018-05-16  15518  	/* notify opregion of the sanitized encoder state */
d6cae4aa3 Maarten Lankhorst 2018-05-16  15519  	intel_opregion_notify_encoder(encoder, connector && has_active_crtc);
70332ac53 Imre Deak         2018-11-01  15520  
70332ac53 Imre Deak         2018-11-01  15521  	if (INTEL_GEN(dev_priv) >= 11)
70332ac53 Imre Deak         2018-11-01  15522  		icl_sanitize_encoder_pll_mapping(encoder);
249293524 Daniel Vetter     2012-07-02  15523  }
249293524 Daniel Vetter     2012-07-02  15524  

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v2] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
  2019-01-09 12:09 [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen Ville Syrjala
  2019-01-10 19:41 ` [Intel-gfx] " kbuild test robot
@ 2019-01-11 17:49 ` " Ville Syrjala
  2019-01-28  9:30   ` [Intel-gfx] " Kahola, Mika
  1 sibling, 1 reply; 5+ messages in thread
From: Ville Syrjala @ 2019-01-11 17:49 UTC (permalink / raw)
  To: intel-gfx; +Cc: stable, Daniel Kamil Kozar

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>
---
 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 5dc0de89c49e..6cd6048b4731 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15438,16 +15438,45 @@ 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_GEN(dev_priv, 6) &&
+		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) {
@@ -15458,16 +15487,25 @@ 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;
 
-- 
2.19.2


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [Intel-gfx] [PATCH v2] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
  2019-01-11 17:49 ` [PATCH v2] " Ville Syrjala
@ 2019-01-28  9:30   ` " Kahola, Mika
  2019-01-28 14:01     ` Ville Syrjälä
  0 siblings, 1 reply; 5+ messages in thread
From: Kahola, Mika @ 2019-01-28  9:30 UTC (permalink / raw)
  To: ville.syrjala, intel-gfx; +Cc: dkk089, stable

The patch look ok to me.

On Fri, 2019-01-11 at 19:49 +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")

Reviewed-by: Mika Kahola <mika.kahola@intel.com>

> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  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 5dc0de89c49e..6cd6048b4731 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15438,16 +15438,45 @@ 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_GEN(dev_priv, 6) &&
> +		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) {
> @@ -15458,16 +15487,25 @@ 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;
>  

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [Intel-gfx] [PATCH v2] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen
  2019-01-28  9:30   ` [Intel-gfx] " Kahola, Mika
@ 2019-01-28 14:01     ` Ville Syrjälä
  0 siblings, 0 replies; 5+ messages in thread
From: Ville Syrjälä @ 2019-01-28 14:01 UTC (permalink / raw)
  To: Kahola, Mika; +Cc: intel-gfx, dkk089, stable

On Mon, Jan 28, 2019 at 09:30:35AM +0000, Kahola, Mika wrote:
> The patch look ok to me.
> 
> On Fri, 2019-01-11 at 19:49 +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")
> 
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>

Thanks. Pushed to dinq.

> 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  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 5dc0de89c49e..6cd6048b4731 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -15438,16 +15438,45 @@ 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_GEN(dev_priv, 6) &&
> > +		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) {
> > @@ -15458,16 +15487,25 @@ 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;
> >  

-- 
Ville Syrjälä
Intel

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, back to index

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-01-09 12:09 [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen Ville Syrjala
2019-01-10 19:41 ` [Intel-gfx] " kbuild test robot
2019-01-11 17:49 ` [PATCH v2] " Ville Syrjala
2019-01-28  9:30   ` [Intel-gfx] " Kahola, Mika
2019-01-28 14:01     ` Ville Syrjälä

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