From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michel =?ISO-8859-1?Q?D=E4nzer?= Subject: Re: [PATCH] Tile Blitting Date: 27 Feb 2003 19:25:03 +0100 Sender: linux-fbdev-devel-admin@lists.sourceforge.net Message-ID: <1046370303.12970.27.camel@thor> References: <1046355210.1206.42.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: Received: from netline-be1.netline.ch ([195.141.226.32]) by sc8-sf-list1.sourceforge.net with esmtp (Exim 3.31-VA-mm2 #1 (Debian)) id 18oSiS-0001Kc-00 for ; Thu, 27 Feb 2003 10:25:08 -0800 In-Reply-To: <1046355210.1206.42.camel@localhost.localdomain> Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="iso-8859-1" To: Antonino Daplas Cc: James Simmons , Linux Fbdev development list On Don, 2003-02-27 at 15:15, Antonino Daplas wrote:=20 > On Thu, 2003-02-27 at 09:18, James Simmons wrote: > =20 > > > Thus, the restriction that the buffer must be completely copied by the > > > driver before returning. And because of this restriction, an extra c= opy > > > which might be unnecessary cannot be avoided (this was noted by Petr). > > >=20 > > > Treating the buffer as a ringbuffer, we eliminate these restrictions. > >=20 > > I didn't realize that the below was a ringbuffer implementation. The na= me > > threw me off.=20 >=20 > Well, it's not strictly a ringbuffer implementation. This would require > a head and tail pointer where fbcon will adjust the tail and the > driver/hardware will adjust the head. This will be very difficult to > implement in a device independent manner. So we just cheat by issuing > an fb_sync() per loop to flush all pending commands. That still seems suboptimal though. What the DRM often does is have the chip write an age value to a scratch register when it's done processing something. Maybe something like that could be used to avoid waiting for the chip to go idle at all? --=20 Earthling Michel D=E4nzer (MrCooper)/ Debian GNU/Linux (powerpc) developer XFree86 and DRI project member / CS student, Free Software enthusiast ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf