On 2012-04-30 11:07 +0200, Maarten Maathuis wrote: > On Mon, Apr 30, 2012 at 12:37 AM, Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > > On Sat, Apr 28, 2012 at 11:33:50AM -0400, Nick Bowler wrote: > >> On 2012-04-28 02:19 -0400, Alex Deucher wrote: > >> > On Fri, Apr 27, 2012 at 8:39 PM, Nick Bowler <nbowler@xxxxxxxxxxxxxxxx> wrote: > >> > > While tracking down the black screen issue, I've been having the monitor > >> > > directly connected to the video card the whole time, but now when I'm > >> > > connected through my KVM switch (an IOGear GCS1804), it appears that > >> > > something's going wrong with reading the EDID, because the available > >> > > modes are all screwed up (both console and X decide they want to drive > >> > > the display at 1024x768). [...] > >> > > Also, looking at /sys/class/drm/card0-VGA-1/edid I see that it > >> > > is empty on 3.4-rc4+ and it is correct on 3.2.15. Things seem > >> > > to work OK when the KVM is not involved. > >> > > >> > Were you ever able to fetch a EDID with the KVM involved? KVMs are > >> > notorious for not connecting the ddc pins. > >> > >> Yes, it works on 3.2.15 as described above. > > > > I have the same (or similar) KVM (not in the office at the moment) and I > > can confirm that with newer kernels EDID fecthing in flaky. It's 50/50 > > if EDED retrieval succeeds or if it fails with: > > > > Apr 26 13:06:57 dtor-d630 kernel: [13464.936336] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 208 [...] > > Earlier kernels were able to retrieve EDEDs reliably. FWIW, for me EDID failure on new kernels is 100% reproducible, and there are no such checksum errors in the log. It's just missing. > Just a crazy thought, but didn't we change some timings related to > EDID retrieval? To make it faster. OK, this time bisecting started off relatively smoothly (doing the same "backwards" bisect on the branch-o-reverts as last time), but then my disk died halfway through... So I'll post the partial bisection results now (11 commits left to test), but I clearly have other things to fix before I can get back to this issue. git bisect start 'drivers/gpu/drm' # good: [9232969e19ae7251a93ab72e405cf71e5109ec05] drm/nv40/pm: implement first type of pwm fanspeed funcs git bisect good 9232969e19ae7251a93ab72e405cf71e5109ec05 # bad: [dea7e0ac45fd28f90bbc38ff226d36a9f788efbf] ttm: fix agp since ttm tt rework git bisect bad dea7e0ac45fd28f90bbc38ff226d36a9f788efbf # good: [d2491567cdbcb87b2682e0948a69d73c4dd8987e] drm/nv50/pm: only touch 0x611200 on nv92- git bisect good d2491567cdbcb87b2682e0948a69d73c4dd8987e # good: [f9f9f536312d4c3ca39502ccf6a3af60cfe38ff4] drm/nouveau/bios: pass drm_device to ROMPTR, rather than nvbios git bisect good f9f9f536312d4c3ca39502ccf6a3af60cfe38ff4 # bad: [d4c2c99bdc8385a0e51ce4ef2df124d14b6b9c9d] drm/nouveau/dp: remove broken display depth function, use the improved one git bisect bad d4c2c99bdc8385a0e51ce4ef2df124d14b6b9c9d Cheers, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
