Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/33189 )
Change subject: soc/intel/common: Skip SoC GT programming based on CONFIG_SKIP_GRAPHICS_ENABLING ......................................................................
Patch Set 2:
(2 comments)
https://review.coreboot.org/#/c/33189/1/src/soc/intel/icelake/graphics.c File src/soc/intel/icelake/graphics.c:
https://review.coreboot.org/#/c/33189/1/src/soc/intel/icelake/graphics.c@48 PS1, Line 48: DDI_A_4_LANES
So it's just more code to copy-paste later. Probably without anyone ever checking if the code guarded by this makes sense for the new platform at all. It seems to me like a bad work- around for bad development practice.
[Subrata] yes, its a bad W/A for early platform agree thats the reason its default n. and its early platform nuisance that we might need to deal with. Irrespective if its happening first time on ICL or not.
If I understand you correctly, the display engine of your early samples works (you can see output on a display) but the graphics acceleration doesn't? But the code guarded here has absolutely nothing to do with graphics acceleration. Pushing this weird workaround with wrong explanations makes it very hard to work together in a community, I can't agree to it. But if you have to, go on.
[Subrata] as i have explained several time, you can bring display either by using sw framebuffer only mode or using hardware acceleration mode. Not using this config we would like to guard any transaction that goes to GT register which is not available on specific parts.
https://review.coreboot.org/#/c/33189/2/src/soc/intel/icelake/graphics.c File src/soc/intel/icelake/graphics.c:
https://review.coreboot.org/#/c/33189/2/src/soc/intel/icelake/graphics.c@50 PS2, Line 50: graphics_gtt_write(DDI_BUF_CTL_A, ddi_buf_ctl);
Subrata, Aamir, do you know any ICL documentation about this […]
This registers are available in ICL EDS vol 1 and only thing that we like to skip if touching these registers on specific parts. Customer receiving early parts has DCL to tell if GT is enable or not.