On Wed, 06 Mar 2013, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > On Wed, Mar 6, 2013 at 3:35 AM, Benson Leung <bleung at chromium.org> wrote: >> I'm working on touch devices Chromium OS, and I've noticed a >> regression between 3.8 and 3.9-rc1, which was posted yesterday. >> >> The hardware in question is a Chromebook Pixel. For this device, we >> have i2c input devices: atmel mxt224s touchpad and atmel mxt1664s >> touchscreen. The touchpad is on bus 1, "i915 gmbus vga" at 1-004b. The >> touchscreen is on bus 2, "i915 gmbus panel" at 2-004a. >> >> I was testing v3.9-rc1 on the Pixel and the touchscreen driver is >> being returned -110 (-ETIMEDOUT) on an i2c_transfer after several >> seconds of both touch devices working correctly. At the time of the >> failure, there are no error messages from GMBUS that I can see, but >> the bus never recovers. I can keep interacting with the touchscreen or >> touchpad, and the interrupts trigger reads, but all subsequent reads >> return -110. >> >> I noticed that between 3.8 and 3.9-rc1, your patch series to add gmbus >> irq support was merged. After bisecting, I found that this commit >> seems to be causing the timeout problem. Reverting it makes the >> problem go away, and the bus is stable. > > Can you please retest with latest drm-intel-fixes merged into -rc1? > Paulo's patch fixes a race in handling PCH interrupts (where the gmbus > hw is) which matches rather well with your description here. Also, some error paths only print with debug on. Did you try with drm.debug=0xe? BR, Jani. > > Thanks, Daniel > >> commit 2c438c0273b76d6cb158f8bdd0aa3ebf66e48a28 >> Author: Daniel Vetter <daniel.vetter at ffwll.ch> >> Date: Sat Dec 1 13:53:46 2012 +0100 >> >> drm/i915: use gmbus irq to wait for gmbus idle >> >> GMBUS_ACTIVE has inverted sense and so doesn't fit into the >> wait_hw_status helper, hence create a new gmbus_wait_idle functions. >> Also, we only care about the idle irq event and nothing else, which >> allows us to use the wait_event_timeout helper directly without >> jumping through hoops to catch NAKs. >> >> Since gen2/3 don't have gmbus interrupts, handle them separately with >> the old wait_for macro. >> >> This shaves another few ms off reading EDID from a hdmi screen on my >> testbox here. EDID reading with interrupt driven gmbus is now as fast >> as with busy-looping gmbus at 28 ms here (with negligible cpu >> overhead). >> >> Reviewed-by: Imre Deak <imre.deak at intel.com> >> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch> >> >> >> Is there anything I can do to help debug this some more? >> >> -- >> Benson Leung >> Software Engineer, Chrom* OS >> bleung at chromium.org > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > _______________________________________________ > dri-devel mailing list > dri-devel at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
