Hi Merlin, On 24.09.2016 21:25, Merlin Büge wrote: > Hello everyone! > > > This is my first post to this mailing list :) > welcome to coreboot ;)
I didn't have the time for a closer look at your logs. But there is one thing coreboot does definitely wrong: The clock configuration. You can see it from the Linux log as it dumps the settings coreboot made first: > [ 6.523864] [drm:drm_mode_debug_printmodeline] Modeline 0:"1440x900" 50 > 87075 1440 1520 1672 1820 900 903 909 961 0x40 0xa > [ 6.523872] [drm:intel_dump_pipe_config] port clock: 87075 vs what Linux sets up later: > [ 8.787651] [drm:drm_mode_debug_printmodeline] Modeline 0:"1440x900" 60 > 104500 1440 1520 1672 1820 900 903 909 961 0x48 0xa > [ 8.787668] [drm:intel_dump_pipe_config] port clock: 104500 Not sure why Linux doesn't get the display running though. But as Linux sometimes reuses register settings set by the firmware there is a slight chance that fixing coreboot would make it work in Linux too. There is a related patch up for review for i945 [1] (older chipset) that fixes a similar issue there. Maybe it applies to gm45 too. The code looks very similar. Regards, Nico [1] https://review.coreboot.org/#/c/16504/ > > I'm trying to get a specific panel working on my Thinkpad T400 which runs > libreboot. It's an WXGA+ MVA panel (CMO G141C1-L01) and I have soldered an > adapter cable for it. From what I have found, nobody succeeded on this mod > yet - > there are some attempts on 51nb.com, but only for the T410. I basically took > some already existing adapter cable, and modified a few pins, so that it would > match up exactly with the datasheets. I used the LG LP141WP2-TLB1 for > reference. > Some details about my adapter cable can be found here: > > http://forum.thinkpads.com/viewtopic.php?f=45&t=121151 > > In the first post there are also links to the datasheets of the two panels in > question. > > Of course I thoroughly checked all my self-made connections and modifications, > but only with some general purpose DMM for continuity. They all seem fine. > > > So far backlight + PWM control works, but I have no image displayed, both in > libreboot (with GRUB2 as payload) and Linux (up-to-date Arch Linux). > > I tried the panel both with the latest stock ROM (3.23/EC 1.06) and with > the latest libreboot release, which is currently 2016090 > (t400_8mb_usqwerty_vesafb.rom in my case). > > Since I have not much experience with such low-level hardware stuff, could > someone maybe help me with this or direct me to some useful direction, how I > can debug this? > > I already tried booting with i915.lvds_channel_mode=2 (since I was not able > to figure out what mode was actually used, because this module parameter is > normally set to "0", which means the channel mode is taken from BIOS). > > I attached the EDIDs of both panels, the coreboot log (cbmem -c) of both > panels, and a kernel log of both panels. I also attached a kernel log of the > MVA panel with drm debbuging enabled (drm.debug=0x1e log_buf_len=1M). Note > that > all of the logs were taken from the T400 with the latest libreboot release. > It would be great if somebody could have a look at it. (I don't understand > much > of it.) > > Here is a picture of the adapter cable, so that you have an idea what it looks > like: https://lut.im/funPftuHF0/3sndAspbdiwOpTN4.jpg > > > I already put *a lot* of effort in this project, and I would be very happy if > it > succeeded at the end of the day. I would design some PCBs then, so that this > would basically become a drop-in replacement. Background is: The T400 is a > very > desirable target for libreboot, since it's build on the latest Intel hardware > currently supported in libreboot for laptops. And (not only in the libreboot > community) it is sadly well known for its rather bad TN panels. Also, it would > be something that I could give back to the libreboot community. > > Since I have not much experience with mailing lists, please correct my of any > 'bad' behavior. > > Thank you for reading this, > and for any advice in advance :) > > > Regards, > > Merlin > -- coreboot mailing list: [email protected] https://www.coreboot.org/mailman/listinfo/coreboot
