This is a note to let you know that I've just added the patch titled drm/i915: Read timings from the correct transcoder in intel_crtc_mode_get() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-read-timings-from-the-correct-transcoder-in-intel_crtc_mode_get.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 7b50f7b24cd6c98541f1af53bddc5b6e861ee8c8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx> Date: Fri, 1 Apr 2016 18:37:25 +0300 Subject: drm/i915: Read timings from the correct transcoder in intel_crtc_mode_get() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> commit 7b50f7b24cd6c98541f1af53bddc5b6e861ee8c8 upstream. intel_crtc->config->cpu_transcoder isn't yet filled out when intel_crtc_mode_get() gets called during output probing, so we should not use it there. Instead intel_crtc_mode_get() figures out the correct transcoder on its own, and that's what we should use. If the BIOS boots LVDS on pipe B, intel_crtc_mode_get() would actually end up reading the timings from pipe A instead (since PIPE_A==0), which clearly isn't what we want. It looks to me like this may have been broken by commit eccb140bca67 ("drm/i915: hw state readout&check support for cpu_transcoder") as that one removed the early initialization of cpu_transcoder from intel_crtc_init(). Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx Cc: Rob Kramer <rob@xxxxxxxxxxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Reported-by: Rob Kramer <rob@xxxxxxxxxxxxxxxxxx> Fixes: eccb140bca67 ("drm/i915: hw state readout&check support for cpu_transcoder") References: https://lists.freedesktop.org/archives/dri-devel/2016-April/104142.html Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/1459525046-19425-1-git-send-email-ville.syrjala@xxxxxxxxxxxxxxx (cherry picked from commit e30a154b5262b967b133b06ac40777e651045898) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_display.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -11471,13 +11471,10 @@ struct drm_display_mode *intel_crtc_mode { struct drm_i915_private *dev_priv = to_i915(dev); struct intel_crtc *intel_crtc = to_intel_crtc(crtc); - enum transcoder cpu_transcoder = intel_crtc->config->cpu_transcoder; + enum transcoder cpu_transcoder; struct drm_display_mode *mode; struct intel_crtc_state *pipe_config; - int htot = I915_READ(HTOTAL(cpu_transcoder)); - int hsync = I915_READ(HSYNC(cpu_transcoder)); - int vtot = I915_READ(VTOTAL(cpu_transcoder)); - int vsync = I915_READ(VSYNC(cpu_transcoder)); + u32 htot, hsync, vtot, vsync; enum pipe pipe = intel_crtc->pipe; mode = kzalloc(sizeof(*mode), GFP_KERNEL); @@ -11505,6 +11502,13 @@ struct drm_display_mode *intel_crtc_mode i9xx_crtc_clock_get(intel_crtc, pipe_config); mode->clock = pipe_config->port_clock / pipe_config->pixel_multiplier; + + cpu_transcoder = pipe_config->cpu_transcoder; + htot = I915_READ(HTOTAL(cpu_transcoder)); + hsync = I915_READ(HSYNC(cpu_transcoder)); + vtot = I915_READ(VTOTAL(cpu_transcoder)); + vsync = I915_READ(VSYNC(cpu_transcoder)); + mode->hdisplay = (htot & 0xffff) + 1; mode->htotal = ((htot & 0xffff0000) >> 16) + 1; mode->hsync_start = (hsync & 0xffff) + 1; Patches currently in stable-queue which might be from ville.syrjala@xxxxxxxxxxxxxxx are queue-4.9/drm-i915-bios-parse-ddi-ports-also-for-chv-for-hdmi-ddc-pin-and-dp-aux-channel.patch queue-4.9/drm-i915-read-timings-from-the-correct-transcoder-in-intel_crtc_mode_get.patch