Re: [Intel-gfx] [PATCH 00/12] Add more DMT and common modes

[Takashi Iwai <tiwai@suse.de>]

At Tue, 17 Apr 2012 17:26:26 +0200,
Takashi Iwai wrote:
> 
> At Fri, 13 Apr 2012 16:56:26 -0400,
> Adam Jackson wrote:
> > 
> > On 4/13/12 4:33 PM, Adam Jackson wrote:
> > > Incorporates some feedback from Rodrigo and Takashi.  Major themes of the
> > > series:
> > >
> > > - Fix the DMT list to include reduced-blanking modes
> > > - Add modes from DMT for any range descriptor type
> > > - Add an extra modes list for things not in DMT
> > > - For ranges that specify a formula, generate timings from the extra modes
> > >
> > > This still doesn't address the driver policy decision of "I know I have
> > > a scaler, add modes as if there were a range descriptor even if there's
> > > not one".  But it should at least make clear what such a helper function
> > > should do.
> > 
> > One minor buglet in this series that's not obvious from inspection (and 
> > that I didn't realize until just now) is that putting 1366x768 in the 
> > minimode list won't do what you want, since the mode you get back will 
> > be 1368x768.  Probably we should move the manual-underscan hack into the 
> > timing generators themselves.
> 
> Sounds like a good compromise.  We have already hacks in drm_edid.c
> for HDMI TV, so one exception more isn't that bad ;)

FYI, I tried the hack below and it seems working.


Takashi

---
---
 drivers/gpu/drm/drm_edid.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1047,6 +1047,19 @@ drm_dmt_modes_for_range(struct drm_conne
 	return modes;
 }
 
+/* fix up 1366x768 mode from 1368x768;
+ * GTF/CVT can't express 1366 width which isn't dividable by 8
+ */
+static void fixup_mode_1366x768(struct drm_display_mode *mode)
+{
+	if (mode->hdisplay == 1368 && mode->vdisplay == 768) {
+		mode->hdisplay = 1366;
+		mode->hsync_start--;
+		mode->hsync_end--;
+		drm_mode_set_name(mode);
+	}
+}
+
 static int
 drm_gtf_modes_for_range(struct drm_connector *connector, struct edid *edid,
 			struct detailed_timing *timing)
@@ -1059,6 +1072,7 @@ drm_gtf_modes_for_range(struct drm_conne
 		const struct minimode *m = &extra_modes[i];
 		newmode = drm_gtf_mode(dev, m->w, m->h, m->r, 0, 0);
 
+		fixup_mode_1366x768(newmode);
 		if (!mode_in_range(newmode, edid, timing)) {
 			drm_mode_destroy(dev, newmode);
 			continue;
@@ -1084,6 +1098,7 @@ drm_cvt_modes_for_range(struct drm_conne
 		const struct minimode *m = &extra_modes[i];
 		newmode = drm_cvt_mode(dev, m->w, m->h, m->r, rb, 0, 0);
 
+		fixup_mode_1366x768(newmode);
 		if (!mode_in_range(newmode, edid, timing)) {
 			drm_mode_destroy(dev, newmode);
 			continue;