From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jike Song <jike.song@intel.com>
Subject: Re: [PATCH 02/11] drm/i915: Clarify event_lock locking,
 irq&mixed context
Date: Mon, 29 Sep 2014 20:45:56 +0800
Message-ID: <54295484.8030604@intel.com>
References: <1410785732-18553-1-git-send-email-daniel.vetter@ffwll.ch>
 <1410785732-18553-3-git-send-email-daniel.vetter@ffwll.ch>
 <5428FA2B.8030005@intel.com> <20140929122012.GE4109@phenom.ffwll.local>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <intel-gfx-bounces@lists.freedesktop.org>
Received: from mga01.intel.com (mga01.intel.com [192.55.52.88])
 by gabe.freedesktop.org (Postfix) with ESMTP id 67DAE6E170
 for <intel-gfx@lists.freedesktop.org>; Mon, 29 Sep 2014 05:50:27 -0700 (PDT)
In-Reply-To: <20140929122012.GE4109@phenom.ffwll.local>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=subscribe>
Errors-To: intel-gfx-bounces@lists.freedesktop.org
Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
List-Id: intel-gfx@lists.freedesktop.org

On 09/29/2014 08:20 PM, Daniel Vetter wrote:
> On Mon, Sep 29, 2014 at 02:20:27PM +0800, Jike Song wrote:
>> On 09/15/2014 08:55 PM, Daniel Vetter wrote:
>>> Now we tackle the functions also called from interrupt handlers.
>>>
>>> - intel_check_page_flip is exclusively called from irq handlers, so a
>>>    plain spin_lock is all we need. In i915_irq.c we have the convention
>>>    to give all such functions an _irq_handler postfix, but that would
>>>    look strange and als be a bit a misleading name. I've opted for a
>>>    WARN_ON(!in_irq()) instead.
>>
>> Hi Daniel,
>>
>>   Is it possible to use in_interrupt() instead? Sorry to tell that, in
>> our iGVT-g implementation, the host i915 irq handler needs to be called
>> in a non hardirq driven context. i.e. a tasklet or workqueue.
>
> Hm, why that? Depending upon how you do this you might break a lot of the
> interrupt related locking we have ... This is a crucial integration issue,
> which patch does that change?
> -Daniel

The RFC patch set is not sent out yet, hopefully in 1~2 days :)

Yes I know it's not a good implementation ... I also wish there would be
a better way to go :)


--
Thanks,
Jike