https://bugzilla.kernel.org/show_bug.cgi?id=24462
Summary: r600: spread spectrum: flickering screen (bisected) Product: Drivers Version: 2.5 Kernel Version: 2.6.37-rc5 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: kronos.it@gmail.com Regression: Yes
2.6.37-rc5 exhibits a slight screen (notebook panel) flickering, mostly noticeable around text (e.g. white-on-black in xterm) with occasional horizontal lines; using 2.6.36 as known "good" kernel I've bisected the issue down to this commit:
ba032a58d1f320039e7850fb6e8651695c1aa571 is the first bad commit commit ba032a58d1f320039e7850fb6e8651695c1aa571 Author: Alex Deucher alexdeucher@gmail.com Date: Mon Oct 4 17:13:01 2010 -0400
drm/radeon/kms: rework spread spectrum handling
This patch reworks spread spectrum handling to enable it properly on lvds and DP/eDP links. It also fixes several bugs in the old spread spectrum code.
- Use the ss recommended reference divider if available when calculating the pll - Use the proper ss command tables on pre-DCE3 asics - Avoid reading past the end of the ss info tables - Enable ss on evergreen asics (lvds, dp, tmds) - Enable ss on DP/eDP links
Signed-off-by: Alex Deucher alexdeucher@gmail.com Signed-off-by: Dave Airlie airlied@redhat.com
:040000 040000 2017e6abb9a12586686bcddb61479f2b158c9d7c 7e6117db061ef286ab6822455c65cf5492de7eaa M drivers
Hardware is a M76: 01:00.0 VGA compatible controller: ATI Technologies Inc M76 [Radeon Mobility HD 2600 Series]
dmesg is attached.
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #1 from Alex Deucher alexdeucher@gmail.com 2010-12-08 17:11:56 --- Created an attachment (id=39252) --> (https://bugzilla.kernel.org/attachment.cgi?id=39252) possible fix
Does this patch help?
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #2 from Luca Tettamanti kronos.it@gmail.com 2010-12-08 20:27:11 --- (In reply to comment #1)
Created an attachment (id=39252)
--> (https://bugzilla.kernel.org/attachment.cgi?id=39252) [details]
possible fix
Does this patch help?
No, flickering it's still there. The parameters passed to EnableSpreadSpectrumOnPPLL with 2.6.36 and 2.6.37-rc5 are:
ss->percentage = 0x1e ss->type = 0x1 ss->step = 0x1 ss->delay = 0x2a ss->range = 0x2 pll_id = 0x0
but 2.6.36 uses ENABLE_SPREAD_SPECTRUM_ON_PPLL_PS_ALLOCATION, while the newer kernel uses ENABLE_LVDS_SS_PARAMETERS_V2 for the parameters (the only difference is that the latter does not have ucPpll); is this correct?
https://bugzilla.kernel.org/show_bug.cgi?id=24462
Alex Deucher alexdeucher@gmail.com changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |alexdeucher@gmail.com
--- Comment #3 from Alex Deucher alexdeucher@gmail.com 2010-12-08 20:39:57 --- Please attach a copy of your vbios: (as root) (use lspci to get the bus id) cd /sys/bus/pci/devices/<pci bus id> echo 1 > rom cat rom > /tmp/vbios.rom echo 0 > rom
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #4 from Luca Tettamanti kronos.it@gmail.com 2010-12-08 20:47:55 --- Created an attachment (id=39342) --> (https://bugzilla.kernel.org/attachment.cgi?id=39342) M76 vbios
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #5 from Alex Deucher alexdeucher@gmail.com 2010-12-08 21:14:47 --- Created an attachment (id=39362) --> (https://bugzilla.kernel.org/attachment.cgi?id=39362) possible fix
(In reply to comment #2)
but 2.6.36 uses ENABLE_SPREAD_SPECTRUM_ON_PPLL_PS_ALLOCATION, while the newer kernel uses ENABLE_LVDS_SS_PARAMETERS_V2 for the parameters (the only difference is that the latter does not have ucPpll); is this correct?
That is correct. I suspect it's the pll that's problematic: if (ss_enabled) { if (ss->refdiv) { pll->flags |= RADEON_PLL_USE_REF_DIV; pll->reference_div = ss->refdiv; } }
It uses a fixed reference divider of 2 in your case. Does the attached patch help? Please also try this patch in conjunction with the patch in comment 1.
https://bugzilla.kernel.org/show_bug.cgi?id=24462
Rafael J. Wysocki rjw@sisk.pl changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |florian@mickler.org, | |maciej.rutecki@gmail.com, | |rjw@sisk.pl Blocks| |21782
--- Comment #6 from Rafael J. Wysocki rjw@sisk.pl 2010-12-08 22:12:17 --- First-Bad-Commit : ba032a58d1f320039e7850fb6e8651695c1aa571
Handled-By : Alex Deucher alexdeucher@gmail.com
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #7 from Luca Tettamanti kronos.it@gmail.com 2010-12-08 22:32:06 --- (In reply to comment #5)
Does the attached patch help? Please also try this patch in conjunction with the patch in comment 1.
Still not working, even with the first patch applied.
https://bugzilla.kernel.org/show_bug.cgi?id=24462
Alex Deucher alexdeucher@gmail.com changed:
What |Removed |Added ---------------------------------------------------------------------------- Attachment #39252|0 |1 is obsolete| | Attachment #39362|0 |1 is obsolete| |
--- Comment #8 from Alex Deucher alexdeucher@gmail.com 2010-12-08 23:05:27 --- Created an attachment (id=39372) --> (https://bugzilla.kernel.org/attachment.cgi?id=39372) possible fix
This patch disables use of the ss fixed ref divide and should fix it.
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #9 from Luca Tettamanti kronos.it@gmail.com 2010-12-09 20:12:05 --- (In reply to comment #8)
This patch disables use of the ss fixed ref divide and should fix it.
Yes, taking out that code worked. I'm of course available for further testing if you're not satisfied with this workaround ;)
https://bugzilla.kernel.org/show_bug.cgi?id=24462
Florian Mickler florian@mickler.org changed:
What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |PATCH_ALREADY_AVAILABLE
--- Comment #10 from Florian Mickler florian@mickler.org 2010-12-17 00:43:13 --- Patch: https://bugzilla.kernel.org/attachment.cgi?id=39372
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #11 from Alex Deucher alexdeucher@gmail.com 2010-12-20 06:57:15 --- I've sent the patch to Dave. It should show up in his next drm pull request.
https://bugzilla.kernel.org/show_bug.cgi?id=24462
Rafael J. Wysocki rjw@sisk.pl changed:
What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |CLOSED Resolution|PATCH_ALREADY_AVAILABLE |CODE_FIX
--- Comment #12 from Rafael J. Wysocki rjw@sisk.pl 2010-12-29 22:48:03 --- Fixed by commit e5fd205 drm/radeon/kms: disable ss fixed ref divide .
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #13 from Alex Deucher alexdeucher@gmail.com 2011-02-11 06:57:54 --- Luca, can you try re-enabling this code with 2.6.38-rc4 or newer? Do you still have problems?
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #14 from Alex Deucher alexdeucher@gmail.com 2011-02-11 07:32:50 --- Created an attachment (id=47282) --> (https://bugzilla.kernel.org/attachment.cgi?id=47282) better fix
Can you try the following patch against 2.6.38-rc4 or newer and make sure all is working well?
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #15 from Luca Tettamanti kronos.it@gmail.com 2011-02-11 16:09:40 --- (In reply to comment #14)
Created an attachment (id=47282)
--> (https://bugzilla.kernel.org/attachment.cgi?id=47282) [details]
better fix
Can you try the following patch against 2.6.38-rc4 or newer and make sure all is working well?
2.6.38-rc4 plus the patch looks good, thanks!
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #16 from Alex Deucher alexdeucher@gmail.com 2011-02-12 01:17:21 --- Created an attachment (id=47482) --> (https://bugzilla.kernel.org/attachment.cgi?id=47482) new patch
Can you try this patch? Try uncommenting the following lines to see if either of those flags work as well. Try them individually and together if possible and report back which, if any, helps.
/*pll->flags |= RADEON_PLL_PREFER_MINM_OVER_MAXP;*/
/*if (ASIC_IS_AVIVO(rdev)) pll->flags |= RADEON_PLL_USE_FRAC_FB_DIV;*/
Thanks!
https://bugzilla.kernel.org/show_bug.cgi?id=24462
--- Comment #17 from Luca Tettamanti kronos.it@gmail.com 2011-02-14 13:56:01 --- (In reply to comment #16)
Created an attachment (id=47482)
--> (https://bugzilla.kernel.org/attachment.cgi?id=47482) [details]
new patch
Can you try this patch? Try uncommenting the following lines to see if either of those flags work as well. Try them individually and together if possible and report back which, if any, helps.
/*pll->flags |= RADEON_PLL_PREFER_MINM_OVER_MAXP;*/
/*if (ASIC_IS_AVIVO(rdev)) pll->flags |= RADEON_PLL_USE_FRAC_FB_DIV;*/
The first one alone works, the second one alone does *not* work, both together work fine.
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