Observed with Intel driver version 2.3.2.
The xrandr output property PANEL_FITTING determines how video modes
smaller than the LCD's native resolution will scale. It has three
values: "center", which does not stretch the image at all,
"full_aspect", which stretches the image but keeps its aspect ratio,
and "full", which stretches the image to the full LCD resolution and
ignores aspect ratio. PANEL_FITTING currently defaults to "full". I
believe it should default to "full_aspect".
Many new laptops have widescreen LCDs, and I would guess that the
majority of explicitly set non-native modes use non-widescreen
resolutions, either to accomodate a game or other fullscreen program
that does not support arbitrary modes, or to match the resolution of
an external display such as a projector.
I believe that preserving the aspect ratio of the display, rather than
distorting it, seems like the more reasonable default.
Fixed in commit 667923559219429b0c5fec12a0164f7eba1f8f2d. If needed we can always change the default on older chipsets, but they should be fixed now so hopefully this will work for everyone.
This worked for a while, but it seems to have regressed recently. xrandr now shows that the "scaling mode" property defaults to "Full", not "Full aspect".
Perhaps something changed during the switch to KMS?
I've observed this regression with 2.9 and 2.11.
Created attachment 36013 [details] [review]
change default fitting mode to full aspect
Yep, looks like the change never got propagated to the kernel. Does this patch work for you?
(In reply to comment #3)
> Created an attachment (id=36013) [details]
> change default fitting mode to full aspect
> Yep, looks like the change never got propagated to the kernel. Does this patch
> work for you?
Confirmed. I built 2.6.34 with this change, and xrandr now shows that "scaling mode" defaults to "Full aspect".
(Also, I noticed that the patch makes the code disagree with the comment directly above it; that comment should probably change to match.)
Thanks for the quick response!
Patch pushed out.
Is this patch applicable to Arrandale?
See https://bugs.launchpad.net/ubuntu/+source/linux/+bug/601370 for further info.
On Wed, 14 Jul 2010 19:06:05 -0700 (PDT)
> --- Comment #6 from madbiologist <email@example.com> 2010-07-14
> 19:06:05 PDT --- Is this patch applicable to Arrandale?
> See https://bugs.launchpad.net/ubuntu/+source/linux/+bug/601370 for
> further info.
Yes, it applies to all chipsets. However, panel fitting for Arrandale
may be different, it sounds like we may not support it at all right
now. But this bug is just about the default behavior.
Please file a new bug for the missing panel fitting controls for