From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: Hugh Dickins <hughd@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>,
Mario Kleiner <mario.kleiner@tuebingen.mpg.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/i915: Suppress spurious vblank interrupts
Date: Tue, 1 Feb 2011 11:32:38 -0800 [thread overview]
Message-ID: <20110201113238.60b33ff9@jbarnes-desktop> (raw)
In-Reply-To: <AANLkTim4kL9OjBDiQQ1MBfOCzThxmDonBic11N45NKxj@mail.gmail.com>
On Tue, 1 Feb 2011 10:46:17 -0800
Hugh Dickins <hughd@google.com> wrote:
> On Tue, Feb 1, 2011 at 10:08 AM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> > On Tue, 1 Feb 2011 09:46:43 -0800
> > Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> >>
> >> Are you still seeing underruns during normal activity?
>
> Yes. That is, I see the "pipe a underrun" messages when I set drm
> debug 7: I'm unaware of any ill-effect from them, unless they are
> indeed a factor in my unflushed text issue.
They can cause your display to shake or flicker, or the memory
controller to get confused enough to hang your system.
> I was surprised that i915_driver_irq_handler "Clear the PIPE(A|B)STAT
> regs" writes back precisely the pipea_stats it reads in, I'd have
> expected to clear something there (and did earlier experiment with
> writing back 0: black screen at boot!). But assumed the protocol is
> such that it acknowledges the status bits by writing same back.
Exactly. High bits are the interrupt enable bits, low bits are set for
status, write of 1 to clear status.
> Right. I haven't double-checked the logic, but I believe it's because
> of bits set in the underrunning pipea_stats. I did one time modify
> the underrun message to print out pipea_stats, over five seconds most
> (265) values were 0x80440207
> (there were also 14 occurrences of 0x80440007, 5 of 0x80440004 and 3
> of 0x80440204).
Well, vblank interrupts are enabled (though they shouldn't be for your
config as far as we know), so the interrupt status and handling is
occurring as expected.
What I find strange is that you're seeing flip pending interrupts. Are
your symptoms affected if you remove the
I915_DISPLAY_PLANE_[AB]_FLIP_PENDING_INTERRUPT lines from
I915_INTERRUPT_ENABLE_FIX at the top of i915_irq.c?
Do you see any calls to drm_mode_page_flip_ioctl() in your environment?
> I just tried i915.powersave=0 but the underruns still appeared. I
> then tried earlier kernels, and was surprised to find no underruns
> with 2.6.34, 2.6.36: the underruns appeared with 2.6.37.
Ok, that rules out self-refresh then I think.
--
Jesse Barnes, Intel Open Source Technology Center
next prev parent reply other threads:[~2011-02-01 19:32 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-20 18:12 [BISECTED] agp/intel: revert "Remove confusion of stolen entries not stolen memory" Arnd Bergmann
2010-12-20 18:53 ` Chris Wilson
2010-12-20 19:47 ` Arnd Bergmann
2010-12-20 19:52 ` Chris Wilson
2010-12-20 20:52 ` Arnd Bergmann
2010-12-20 21:06 ` Chris Wilson
2010-12-20 21:54 ` Arnd Bergmann
2010-12-20 22:08 ` Dave Airlie
2011-01-20 23:24 ` Frederic Weisbecker
2011-01-21 10:58 ` [PATCH] drm/i915,agp/intel: Do not clear stolen entries Chris Wilson
2011-01-21 16:26 ` Jiri Olsa
2011-01-23 1:12 ` Frederic Weisbecker
2011-01-23 11:01 ` Chris Wilson
2011-01-23 17:59 ` Frederic Weisbecker
2011-01-24 7:40 ` Hugh Dickins
2011-01-24 10:10 ` Chris Wilson
2011-01-26 21:39 ` Arnd Bergmann
2011-01-28 22:00 ` Hugh Dickins
2011-01-29 2:59 ` Mario Kleiner
2011-01-30 0:28 ` Hugh Dickins
2011-01-30 4:13 ` Mario Kleiner
2011-01-30 9:55 ` Chris Wilson
2011-01-31 10:57 ` [PATCH] drm/i915: Suppress spurious vblank interrupts Chris Wilson
2011-02-01 17:34 ` Hugh Dickins
2011-02-01 17:46 ` Chris Wilson
2011-02-01 17:46 ` Jesse Barnes
2011-02-01 18:08 ` Jesse Barnes
2011-02-01 18:46 ` Hugh Dickins
2011-02-01 19:32 ` Jesse Barnes [this message]
2011-02-02 3:37 ` Hugh Dickins
2011-02-02 17:18 ` Jesse Barnes
2011-02-08 19:52 ` Hugh Dickins
2011-02-10 10:16 ` [PATCH] drm/i915/tv: Use polling rather than interrupt-based hotplug Chris Wilson
2011-02-11 6:34 ` Hugh Dickins
2011-02-11 18:21 ` [PATCH] drm/i915: Suppress spurious vblank interrupts Mario Kleiner
2011-02-14 17:41 ` Hugh Dickins
2011-06-18 4:40 ` Hugh Dickins
2011-01-30 8:52 ` [PATCH] drm/i915,agp/intel: Do not clear stolen entries Chris Clayton
2011-01-21 16:05 ` [BISECTED] agp/intel: revert "Remove confusion of stolen entries not stolen memory" Jiri Olsa
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