the following patch was just integrated into master: commit 07e206a6466197487f9f877ee6f5e7a7bec751a2 Author: Nico Huber nico.huber@secunet.com Date: Wed Oct 19 15:20:17 2016 +0200
nb/intel/sandybridge/gma: Always initialize DP buffer translation
These settings should be always made by the firmware, no matter if we set up graphics or not. It looks like Linux doesn't even know these registers.
The values are taken from the PRMs for Sandy Bridge and Ivy Bridge [1, 2]. They match the settings that were done in the native graphics path for Ivy Bridge. I expect the differences to be an update (i.e. the set- tings we did on the Sandy Bridge path were just outdated). Also, these settings affect the PCH and not the CPU which are independent from each other.
[1] Intel® OpenSource HD Graphics Programmer’s Reference Manual (PRM) Volume 3 Part 3: PCH Display Registers (SandyBridge) Doc Ref #: IHD-OS-V3 Pt3 – 05 11 https://01.org/sites/default/files/documentation/snb_ihd_os_vol3_part3.pdf
[2] Intel ® OpenSource HD Graphics Programmer’s Reference Manual (PRM) Volume 3 Part 4: South Display Engine Registers (Ivy Bridge) Doc Ref #: IHD-OS-V3 Pt 4 – 05 12 https://01.org/sites/default/files/documentation/ivb_ihd_os_vol3_part4.pdf
Change-Id: I83cc90c7558b93273a727f332fb0d8ced47ed70e Signed-off-by: Nico Huber nico.huber@secunet.com Reviewed-on: https://review.coreboot.org/17073 Tested-by: build bot (Jenkins) Reviewed-by: Arthur Heymans arthur@aheymans.xyz Reviewed-by: Paul Menzel paulepanter@users.sourceforge.net
See https://review.coreboot.org/17073 for details.
-gerrit