From: Ben Widawsky <ben@bwidawsk.net>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 4/4] drm/i915: optional fewer warning patch
Date: Sat, 9 Apr 2011 16:32:04 -0700 [thread overview]
Message-ID: <20110409233203.GA5736@lundgren.kumite> (raw)
In-Reply-To: <849307$cd80vp@azsmga001.ch.intel.com>
On Sat, Apr 09, 2011 at 11:31:14PM +0100, Chris Wilson wrote:
> On Sat, 9 Apr 2011 13:31:22 -0700, Ben Widawsky <ben@bwidawsk.net> wrote:
> > + *
> > + * Intelligent users of the interface may do a force_wake_get() followed
> > + * by many register reads and writes, knowing that the reference count
> > + * is already incremented. So we do not want to warn on those.
> > */
>
> Hmm, any place where we touch registers without holding a lock, unless
> under exceptional conditions such as !SYSTEM_RUNNING, is a bug waiting to
> happen. And probably already happened. Nasty, hard to reproduce race
> conditions.
The only use I had in mind was doing a bunch of reads, or perhaps
polling on a register. I didn't have a specific case but it seemed
feasible in certain cases.
> -Chris
Ben
prev parent reply other threads:[~2011-04-09 23:32 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-08 17:47 forcewake junk, RFC, RFT(test) Ben Widawsky
2011-04-08 17:47 ` [PATCH 1/4] drm/i915: proper use of forcewake Ben Widawsky
2011-04-08 17:47 ` [PATCH 2/4] drm/i915: refcounts for forcewake Ben Widawsky
2011-04-08 17:47 ` [PATCH 3/4] drm/i915: userspace interface to the forcewake refcount Ben Widawsky
2011-04-08 17:47 ` [PATCH 4/4] drm/i915: optional fewer warning patch Ben Widawsky
2011-04-09 20:26 ` forcewake junk, part2 Ben Widawsky
2011-04-09 20:26 ` (no subject) Ben Widawsky
[not found] ` <1302380787-2957-3-git-send-email-ben@bwidawsk.net>
2011-04-09 20:26 ` [PATCH 1/4] drm/i915: proper use of forcewake Ben Widawsky
2011-04-09 20:26 ` [PATCH 2/4] drm/i915: refcounts for forcewake Ben Widawsky
2011-04-09 20:26 ` [PATCH 3/4] drm/i915: userspace interface to the forcewake refcount Ben Widawsky
2011-04-09 20:31 ` forcewake patches (ignore previous, please) Ben Widawsky
2011-04-09 20:31 ` [PATCH 1/4] drm/i915: proper use of forcewake Ben Widawsky
2011-04-09 20:31 ` [PATCH 2/4] drm/i915: refcounts for forcewake Ben Widawsky
2011-04-09 20:31 ` [PATCH 3/4] drm/i915: userspace interface to the forcewake refcount Ben Widawsky
2011-04-09 20:31 ` [PATCH 4/4] drm/i915: optional fewer warning patch Ben Widawsky
2011-04-09 22:31 ` Chris Wilson
2011-04-09 23:32 ` Ben Widawsky [this message]
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