Attachment 143020 Details for Bug 109245 – [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen

[patch] [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by broken SNB BIOSen

0001-drm-i915-Try-to-sanitize-bogus-DPLL-state-left-over-.patch (text/plain), 4.94 KB, created by Ville Syrjala on 2019-01-08 20:56:39 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Ville Syrjala

Created: 2019-01-08 20:56:39 UTC

Size: 4.94 KB

patch

obsolete

>From d012796f64145a03ddf48b5f40e118093a6bf594 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Tue, 8 Jan 2019 22:20:36 +0200
>Subject: [PATCH] drm/i915: Try to sanitize bogus DPLL state left over by
> broken SNB BIOSen
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>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>
>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 SyrjÃ¤lÃ¤ <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
>

Actions: View | Splinter Review

Attachments on bug 109245: 143003 | 143017 | 143020

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.