On Tue, 30 Oct 2012, Jani Nikula jani.nikula@intel.com wrote:
Hi Ted -
On Tue, 30 Oct 2012, Theodore Ts'o tytso@mit.edu wrote:
I recently upgraded to 3.6.3, and my Lenovo X230 has stopped being able to work with an HP ZR30w 30" 2560x1600 display. I saw the following messages in the dmesg:
[drm:ivb_manual_fdi_link_train] *ERROR* FDI train 1 fail! [drm:ivb_manual_fdi_link_train] *ERROR* FDI train 2 fail!
.. which I didn't see before; the exact same mini-displayport to displayport cable connecting the same Lenovo X230 laptop to exactly the same ZRW 30 display worked just fine with the 3.6.0 kernel.
So I bisected the problem, and found the following commit. Reverting this commit made the problem go away. Maybe we should revert 0c96c65b48fb in mainline?
Thanks for bisecting. However, the commit does fix a bug for some people out there, which is why it's been backported to stable. Without it, we fail to dither when there is not enough bandwidth in the DP link. My guess is that this brings up another bug that affects you, and IMHO we'd be better off debugging this than reverting.
Let me know if you'd like me to do any further debugging.
Something to try would be the latest i915.ko driver [1], which I believe has some link training changes, and/or posting the dmesg with drm.debug=0xe module parameter.
BR, Jani.
[1] drm-intel-next-queued branch at git://people.freedesktop.org/~danvet/drm-intel
Hmm, actually not. Either drm-intel-fixes branch, or Linus' master.
Daniel, 'git tag --contains 0c96c65b48fba3ffe9822a554cbc0cd610765cd5' says the commit is upstream since v3.7-rc1, and you backmerged v3.7-rc2 to drm-intel-next-queued with c2fb7916927e989ea424e61ce5fe617e54878827, but the adjusted_mode fix is nowhere to be seen. Did something go wrong with the backmerge, or am I missing something?
BR, Jani.