All of lore.kernel.org
 help / color / mirror / Atom feed
From: Chris Wilson <chris@chris-wilson.co.uk>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 2/2] drm/i915: Simplify the IVB interrupt handler
Date: Sun, 06 May 2012 16:44:59 +0100	[thread overview]
Message-ID: <1336319107_167879@CP5-2952> (raw)
In-Reply-To: <20120506153750.GB4756@phenom.ffwll.local>

On Sun, 6 May 2012 17:37:50 +0200, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Wed, May 02, 2012 at 09:52:13AM +0100, Chris Wilson wrote:
> > Reduce the number of reads and writes required for handling a single
> > interrupt.
> > 
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> Ok, I've looked at this again and imo it does too much. On a quick look we
> have adding the pch_iir argument to pch_irq_handler and restructuring the
> register read/write sequence in the actual handler. The latter seems to
> require that we unconditionally return IRQ_HANDLED.

This being an MS| directed, and never shared, interrupt, this handler
should not be called unless we have something to do. A IRQ_NONE return
here is a serious bug. Another bug is that we read the PCH IIR twice and
only write back the original value, opening the possiblity of handling
the same interrupt twice. All of which is sumised by reducing the number
of reads and writes required for handing a single interrupt.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

  reply	other threads:[~2012-05-06 15:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-02  8:52 [PATCH 1/2] drm/i915: Support pageflipping interrupts for all 3-pipes on IVB Chris Wilson
2012-05-02  8:52 ` [PATCH 2/2] drm/i915: Simplify the IVB interrupt handler Chris Wilson
2012-05-06 15:37   ` Daniel Vetter
2012-05-06 15:44     ` Chris Wilson [this message]
2012-05-09 20:45     ` [PATCH 1/2] drm/i915: Avoid a double-read of PCH_IIR during interrupt handling Chris Wilson
2012-05-09 20:45       ` [PATCH 2/2] drm/i915: Simplify interrupt processing for IvyBridge Chris Wilson
2012-05-10  9:56         ` Daniel Vetter
2012-05-02 19:46 ` [PATCH 1/2] drm/i915: Support pageflipping interrupts for all 3-pipes on IVB Jesse Barnes
2012-05-06 15:34   ` Daniel Vetter
2012-05-06 16:30     ` Jesse Barnes

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1336319107_167879@CP5-2952 \
    --to=chris@chris-wilson.co.uk \
    --cc=daniel@ffwll.ch \
    --cc=intel-gfx@lists.freedesktop.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.