Bug 58911

Summary:	gma500_gfx: Intel GMA600 tries to output to inaccessible MIPI display
Product:	Drivers	Reporter:	Kevin Becker (khbecker)
Component:	Video(DRI - Intel)	Assignee:	Patrik Jakobsson (patrik.r.jakobsson)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	alan, intel-gfx-bugs, patrik.r.jakobsson
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.9.3	Subsystem:
Regression:	No	Bisected commit-id:

Description Kevin Becker 2013-05-28 14:40:09 UTC

I'm testing a Versalogic Falcon board ( http://www.versalogic.com/products/ds.asp?productid=230 ) that has Intel GMA600 graphics. This board has SVDO and LVDS display outputs, but only the LVDS output is accessible. When the gma500_gfx driver loads, I lose the LVDS display. I see the following message in dmesg:

[drm] internal display is MIPI display

This leads me to believe that the driver is trying to use the SVDO output.

I found a similar issue on the LKML. This email thread included a patch that includes this board (ID 4108) in IS_MRST. It can be found at https://lkml.org/lkml/2012/6/12/175 . This patch fixes the issue for me. After loading the gma500_gfx driver with the patch, the LVDS display output stays on, I can load X using the modesetting driver and I now see the following in dmesg:

[drm] internal display is LVDS display

Comment 1 Patrik Jakobsson 2013-06-08 20:04:47 UTC

These boards doesn't seem to have a VBIOS so they need the Moorestown way of identifying the outputs. I still think it was a bug that the bitmask was excluded for 4108 but it needs to be tested and confirmed.

I've taken over maintenance of the driver so I'll add this to my todo-list. If you are planning to deploy many of these devices please consider donating me one because I have no Oaktrail hardware and thus having a hard time keeping it up to date with the rest of the chips.

-Patrik

Comment 2 Kevin Becker 2013-06-13 12:53:12 UTC

We've decided against using this board for our project and will be sending it back soon, so I won't be able to test further or send you one.

Comment 3 Alan 2013-11-13 20:12:09 UTC

4108 if I remember rightly is Tunnel Creek (E600T or somesuch) not GMA600 - similar enough the main display happens to work but not the same beast.