From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 11/12 v2] drm/i915: wait render timeout ioctl Date: Fri, 27 Apr 2012 16:24:24 +0100 Message-ID: <1335540301_69364@CP5-2952> References: <1335481389-7232-1-git-send-email-ben@bwidawsk.net> <1335481389-7232-12-git-send-email-ben@bwidawsk.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (smtp.fireflyinternet.com [109.228.6.236]) by gabe.freedesktop.org (Postfix) with ESMTP id 02CCB9E77C for ; Fri, 27 Apr 2012 08:25:08 -0700 (PDT) In-Reply-To: <1335481389-7232-12-git-send-email-ben@bwidawsk.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org Cc: Ben Widawsky List-Id: intel-gfx@lists.freedesktop.org On Thu, 26 Apr 2012 16:03:08 -0700, Ben Widawsky wrote: > This helps implement glClientWaitSync. > > Finally we can use the new timed seqno waiting function to allow > userspace to wait on a request with a timeout. This implements that > interface. > > The new ioctl is very straight forward, there is a flags field which I > envision may be useful for various flush permutations of the command. What are the semantics of the ioctl? A simple use case would help specify the interface here. In particular, I can't tell whether the return value (timeout_ns) is meant to be the time elapsed or the time remaining. What value is returned in the timeout if we are interrupted before the wait completes? Would end = gettimeofday() + timeout; do { ret = i915_gem_wait(handle, 0, &timeout); } while (ret == -1 && errno == EINTR); assert(gettimeofday() <= end); wait forever, or until the original timeout expires? -Chris -- Chris Wilson, Intel Open Source Technology Centre