On Wed, Aug 01, 2012 at 06:47:58PM -0700, ron minnich wrote: > Dear intel graphics experts: > > I am looking at trying to get coreboot to move away from binary video > bios on google chromebook platforms. The current target is an > ivybridge system. We'd like to get minimal graphics going with a > source-based startup code in coreboot, such that we can avoid the > issues that come with binary video bioses. > > The good news is that the kernel driver works fine without a video > bios having been run -- the new samsung chromebox/chromebook work in > this manner. > > As an experiment, I have used cocinnelle to extract the relevant > driver functions from the kernel (in this case 3.4.2) and am running > them in user mode. I've had good luck with prototyping hardware > drivers for coreboot in user mode, and this approach is *almost* > working on this graphics hardware. > > You can see the result here: http://pastebin.com/3e77Y66C > > The I2C is working, and I'm recovering EDID and the mode. I can > control the panel backlight. I can easily program the GTT and other > simple functions. Sounds rather awesome ;-) > The issue now is that I am not able to get the link trained. I figure > I'm misordering or missing some crucial step, and on the off chance > that some one of you can look at that output and say "Ron you idiot! > You're missing *this* step" I've posted it. > > If anyone has any thoughts on this I'd welcome them. This thing is > close, and I feel it is possible, but I've obviously got something > wrong. > > Thanks in advance for any help or advice you can give me! DP link training is a feeble beast, and we've fixed quite a few issues just recently. I suggest you retry with the drm/i915 code from 3.6-rc1, in particular the following two patches: commit 0d71068835e2610576d369d6d4cbf90e0f802a71 Author: Paulo Zanoni <paulo.r.zanoni at intel.com> Date: Fri Jun 29 16:03:34 2012 -0300 drm/i915: try to train DP even harder commit 2514bc510d0c3aadcc5204056bb440fa36845147 Author: Jesse Barnes <jbarnes at virtuousgeek.org> Date: Thu Jun 21 15:13:50 2012 -0700 drm/i915: prefer wide & slow to fast & narrow in DP configs Cheers, Daniel [Note that not all these fixes are cc: stable, since we fear that they might blow up on onther configurations - these things always need tons of testing.] -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
