Messages in this thread Patch in this message | | | Date | Fri, 28 Jan 2011 14:00:07 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH] drm/i915,agp/intel: Do not clear stolen entries |
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Sorry, this is now abount vblank or scanout rather than stolen entries.
On Mon, 24 Jan 2011, Chris Wilson wrote: > On Sun, 23 Jan 2011 23:40:41 -0800 (PST), Hugh Dickins <hughd@google.com> wrote: > > > On this laptop I'm typing from (GM965 with KMS), I've had no trouble > > getting X up; but when typing in one of the xterms, typed characters > > often stop echoing, until I shift to a different window, whereupon > > they appear. This condition cleared (for a while) by switching to > > VESA fb console and back; no such problem observed on that console. > > > > Does that sound familiar? I have no evidence whatever that i915 is > > to blame here. Several times I tried bisecting last week, but each > > attempt ended up in a nonsensical place, because the effect does not > > occur to order. So I'd sometimes mark a bisection point as good when > > I guess it must actually have been bad. Perhaps it's a matter of > > timing or an uninitialized variable. But while I'm here, worth asking > > if that behaviour sounds like anything you might be responsible for? > > Sounds suspiciously like the batch buffer is not being dispatched and > flushed to the scanout. A very similar bug was recently fixed for > xf86-video-intel 2.14.0 which was causing deferred output.
I made a more patient bisection during the week, on x86_64 which seemed more consistent than i386, and this time it converged sensibly: to commit 0af7e4dff50454905092d468e91c1ef92e10e6b4 drm/i915: Add support for precise vblank timestamping (v2)
Which kindly notes in its commit message: This code has been only tested on a HP-Mini Netbook with Atom processor and Intel 945GME gpu. The codepath for (IS_G4X(dev) || IS_GEN5(dev) || IS_GEN6(dev)) gpu's has not been tested so far due to lack of hardware. so not surprising that it doesn't work on GM965.
I'm now running with this silly revert:
--- a/drivers/gpu/drm/i915/i915_drv.c 2011-01-18 22:04:29.000000000 -0800 +++ b/drivers/gpu/drm/i915/i915_drv.c 2011-01-24 19:35:51.000000000 -0800 @@ -674,8 +674,8 @@ static struct drm_driver driver = { .device_is_agp = i915_driver_device_is_agp, .enable_vblank = i915_enable_vblank, .disable_vblank = i915_disable_vblank, - .get_vblank_timestamp = i915_get_vblank_timestamp, - .get_scanout_position = i915_get_crtc_scanoutpos, + .get_vblank_timestamp = NULL /* i915_get_vblank_timestamp */, + .get_scanout_position = NULL /* i915_get_crtc_scanoutpos */, .irq_preinstall = i915_driver_irq_preinstall, .irq_postinstall = i915_driver_irq_postinstall, .irq_uninstall = i915_driver_irq_uninstall, which makes 2.6.38-rc usable; though I do believe that I've seen the same issue (unflushed text) occur a couple of times since, much too rare to bisect or get upset by, but indicative of some remaining bug.
Hugh
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