fb: nvidiafb: Try harder at initial mode setting.

The current nvidiafb_check_var() simply bails out if the selected mode is
out of range of the panel dimensions.  A good question would be why the
bogus mode is being selected in the first place -- the panel dimensions
that are read back are certainly bogus, but alas, I have no idea where to
even begin looking at the i2c/EDID/DDC mess:

nvidiafb: Device ID: 10de0165
nvidiafb: CRTC0 analog not found
nvidiafb: CRTC1 analog not found
nvidiafb: EDID found from BUS1
nvidiafb: CRTC 0 is currently programmed for DFP
nvidiafb: Using DFP on CRTC 0
nvidiafb: Panel size is 1280 x 1024
nvidiafb: Panel is TMDS
nvidiafb: unable to setup MTRR
nvidiafb: Flat panel dithering disabled
nvidiafb: PCI nVidia NV16 framebuffer (64MB @ 0xC0000000)

In my .config I presently have:

CONFIG_FIRMWARE_EDID=y
CONFIG_FB_DDC=y
CONFIG_FB_NVIDIA_I2C=y

I've not tried fiddling with these options, as I haven't the vaguest idea
what I should be looking at.

As a workaround, simply groveling for a new mode based on the probed
dimensions seems to work ok.  While it would be nice to debug this further
and sort out why the panel information is bogus, I think it's still worth
retrying the mode based on the panel information at hand as a last-ditch
effort, rather than simply bailing out completely.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Antonino A. Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/video/nvidia/nvidia.c b/drivers/video/nvidia/nvidia.c
index 30e14eb1f51..74517b1b26a 100644
--- a/drivers/video/nvidia/nvidia.c
+++ b/drivers/video/nvidia/nvidia.c
@@ -849,9 +849,27 @@ static int nvidiafb_check_var(struct fb_var_screeninfo *var,
 	if (!mode_valid && info->monspecs.modedb_len)
 		return -EINVAL;
 
+	/*
+	 * If we're on a flat panel, check if the mode is outside of the
+	 * panel dimensions. If so, cap it and try for the next best mode
+	 * before bailing out.
+	 */
 	if (par->fpWidth && par->fpHeight && (par->fpWidth < var->xres ||
-					      par->fpHeight < var->yres))
-		return -EINVAL;
+					      par->fpHeight < var->yres)) {
+		const struct fb_videomode *mode;
+
+		var->xres = par->fpWidth;
+		var->yres = par->fpHeight;
+
+		mode = fb_find_best_mode(var, &info->modelist);
+		if (!mode) {
+			printk(KERN_ERR PFX "mode out of range of flat "
+			       "panel dimensions\n");
+			return -EINVAL;
+		}
+
+		fb_videomode_to_var(var, mode);
+	}
 
 	if (var->yres_virtual < var->yres)
 		var->yres_virtual = var->yres;