On Mon, Apr 30, 2012 at 11:07 AM, Maarten Maathuis <madman2003 at gmail.com>
wrote:
> On Mon, Apr 30, 2012 at 12:37 AM, Dmitry Torokhov
> <dmitry.torokhov at gmail.com> 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 at
>>> > elliptictech.com> wrote:
>>> > > Hi Ben,
>>> > >
>>> > > On 2012-04-27 15:20 +1000, Ben Skeggs wrote:
>>> > >> Does this patch help you at all?
>>> > >>
>>> > >> http://cgit.freedesktop.org/nouveau/linux-2.6/commit/?id=a3a285f17867f0018de798b5ee85731ec1268305
>>> > >
>>> > > Yes. ?I cherry-picked this patch on top of Linus' master (3.4-rc4+) and
>>> > > this appears to solve the "black screen on VGA" problem described in the
>>> > > original report. ?Thanks!
>>> > >
>>> > > Unfortunately, that's not the end of my VGA-related regressions. :(
>>> > >
>>> > > 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). ?Here's the output of xrandr on 3.2.15:
>>> > >
>>> > > ?% xrandr
>>> > > ?Screen 1: minimum 320 x 200, current 1600 x 1200, maximum 4096 x 4096
>>> > > ?VGA-1 connected 1600x1200+0+0 (normal left inverted right x axis y
>>> > > axis) 352mm x 264mm
>>> > > ? ? 1600x1200 ? ? ?75.0*+ ? 70.0 ? ? 65.0 ? ? 60.0
>>> > > ? ? 1280x1024 ? ? ?85.0 + ? 75.0 ? ? 60.0
>>> > > ? ? 1920x1440 ? ? ?60.0
>>> > > ? ? 1856x1392 ? ? ?60.0
>>> > > ? ? 1792x1344 ? ? ?60.0
>>> > > ? ? 1920x1200 ? ? ?74.9 ? ? 59.9
>>> > > ? ? 1680x1050 ? ? ?84.9 ? ? 74.9 ? ? 60.0
>>> > > ? ? 1400x1050 ? ? ?85.0 ? ? 74.9 ? ? 60.0
>>> > > ? ? 1440x900 ? ? ? 84.8 ? ? 75.0 ? ? 59.9
>>> > > ? ? 1280x960 ? ? ? 85.0 ? ? 60.0
>>> > > ? ? 1360x768 ? ? ? 60.0
>>> > > ? ? 1280x800 ? ? ? 84.9 ? ? 74.9 ? ? 59.8
>>> > > ? ? 1152x864 ? ? ? 75.0
>>> > > ? ? 1280x768 ? ? ? 84.8 ? ? 74.9 ? ? 59.9
>>> > > ? ? 1024x768 ? ? ? 85.0 ? ? 75.1 ? ? 75.0 ? ? 70.1 ? ? 60.0 ? ? 43.5 ?
>>> > > ? 43.5
>>> > > ? ? 832x624 ? ? ? ?74.6
>>> > > ? ? 800x600 ? ? ? ?85.1 ? ? 72.2 ? ? 75.0 ? ? 60.3 ? ? 56.2
>>> > > ? ? 848x480 ? ? ? ?60.0
>>> > > ? ? 640x480 ? ? ? ?85.0 ? ? 75.0 ? ? 72.8 ? ? 72.8 ? ? 66.7 ? ? 60.0 ?
>>> > > ? 59.9
>>> > > ? ? 720x400 ? ? ? ?85.0 ? ? 87.8 ? ? 70.1
>>> > > ? ? 640x400 ? ? ? ?85.1
>>> > > ? ? 640x350 ? ? ? ?85.1
>>> > > ? ? 320x200 ? ? ? 165.1
>>> > >
>>> > > And on 3.4-rc4+ (with your patch cherry-picked):
>>> > >
>>> > > ?% xrandr
>>> > > ?Screen 1: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096
>>> > > ?VGA-1 connected 1024x768+0+0 (normal left inverted right x axis y
>>> > > axis) 0mm x 0mm
>>> > > ? ? 1024x768 ? ? ? 60.0*
>>> > > ? ? 800x600 ? ? ? ?60.3 ? ? 56.2
>>> > > ? ? 848x480 ? ? ? ?60.0
>>> > > ? ? 640x480 ? ? ? ?59.9
>>> > > ? ? 320x200 ? ? ? 165.1
>>> > >
>>> > > Running xrandr on 3.4-rc4+ also causes the screen to go black for a
>>> > > second when it does not on 3.2.15. ?It also causes several messages of
>>> > > the form
>>> > >
>>> > > ?[drm] nouveau 0000:01:00.0: Load detected on output B
>>> > >
>>> > > to be logged. ?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
>> Apr 26 13:06:57 dtor-d630 kernel: [13464.955317] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 26 13:06:57 dtor-d630 kernel: [13464.973879] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.087659] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.107147] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.126908] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.146277] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.297659] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>> Apr 27 09:13:03 dtor-d630 kernel: [44602.317063] [drm:drm_edid_block_valid]
>> *ERROR* EDID checksum is invalid, remainder is 208
>>
>> Earlier kernels were able to retrieve EDEDs reliably.
>>
>> This is with:
>>
>> [ ? ?1.678392] [drm] nouveau 0000:01:00.0: Detected an NV50 generation card
>> (0x086b00a2)
>
> Just a crazy thought, but didn't we change some timings related to
> EDID retrieval? To make it faster.
Hum, this commit:
commit 1849ecb22fb3b5d57b65e7369a3957adf9f26f39
Author: Jean Delvare <jdelvare at suse.de>
Date: Sat Jan 28 11:07:09 2012 +0100
drm/kms: Make i2c buses faster
doubled the data rate but only for radeon and intel drivers. nouveau
doesn't use the standard i2c-algo-bit helpers (BTW: the cond_resched()
has been removed), and AFAICS it's using 1us delay; the other drivers
are using 10us, 1us seems a bit too low...
Luca
