[PATCH 2/2] drm/i915: don't always force the panel's fixed_mode

[PATCH 2/2] drm/i915: don't always force the panel's fixed_mode

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

My laptop has two 1440x900 modes: one is the fixed_mode and the other
has different timings. If I use xrandr to switch from the fixed mode to
the "other" 1440x900 mode, xrandr will tell me the change was
successful, but nothing was actually done: I'm still using the
fixed_mode. This patch allows us to use other modes if hdisplay and
vdisplay are the same.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
 drivers/gpu/drm/i915/intel_panel.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

Apply on top of danvet's interlaced branch.

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 230a141..62ca771 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -36,6 +36,12 @@ void
 intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
 		       struct drm_display_mode *adjusted_mode)
 {
+	/* Allow modes that match the panel fixed_mode resolution but have
+	 * different timings */
+	if (adjusted_mode->hdisplay == fixed_mode->hdisplay &&
+	    adjusted_mode->vdisplay == fixed_mode->vdisplay)
+		return;
+
 	adjusted_mode->hdisplay = fixed_mode->hdisplay;
 	adjusted_mode->hsync_start = fixed_mode->hsync_start;
 	adjusted_mode->hsync_end = fixed_mode->hsync_end;
-- 
1.7.8.3

Re: [PATCH 2/2] drm/i915: don't always force the panel's fixed_mode

[Daniel Vetter]

On Fri, Feb 03, 2012 at 05:48:21PM -0200, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> My laptop has two 1440x900 modes: one is the fixed_mode and the other
> has different timings. If I use xrandr to switch from the fixed mode to
> the "other" 1440x900 mode, xrandr will tell me the change was
> successful, but nothing was actually done: I'm still using the
> fixed_mode. This patch allows us to use other modes if hdisplay and
> vdisplay are the same.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Hm, I've thought we should only use this to dynamically switch between a
mode with high refresh rate and one with a low one. Otoh we have a bunch
of boards where we need a generic 'ignore lvds fixed mode because it's
actually not a panel' - I think that would be slightly more useful since
we could then quirk that. But who knows, I don't have much clue ...
-Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [PATCH 2/2] drm/i915: don't always force the panel's fixed_mode

[Chris Wilson]

On Wed, 8 Feb 2012 23:53:10 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Feb 03, 2012 at 05:48:21PM -0200, Paulo Zanoni wrote:
> > From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > 
> > My laptop has two 1440x900 modes: one is the fixed_mode and the other
> > has different timings. If I use xrandr to switch from the fixed mode to
> > the "other" 1440x900 mode, xrandr will tell me the change was
> > successful, but nothing was actually done: I'm still using the
> > fixed_mode. This patch allows us to use other modes if hdisplay and
> > vdisplay are the same.
> > 
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> Hm, I've thought we should only use this to dynamically switch between a
> mode with high refresh rate and one with a low one.

I hesitated for the same reason. Except that by filtering out all modes
except for the one true mode, we prevent the user from being able to
make a choice. They'll invariably make the wrong choice and file a bug,
but nevertheless... ;-)

I also don't think this is the way we want to approach this. The overrides
required for fake LVDS headers would seem to be a superset of this
functionality.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre