From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Airlie Subject: Re: [PATCH 0/2] fbdev: add fillrect and copyarea ioctls Date: Tue, 14 Jul 2009 13:56:55 +1000 Message-ID: <21d7e9970907132056i1dd2eefbn290cb9ad8d318706@mail.gmail.com> References: <20090713151709.GA1297@lilem.mirepesht> <20090713084058.547e88f0@infradead.org> <20090713162559.GA1279@lilem.mirepesht> <21d7e9970907131746q4f1a34efw9d3e6efaa78aea34@mail.gmail.com> <20090714034353.GA1280@lilem.mirepesht> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20090714034353.GA1280@lilem.mirepesht> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Ali Gholami Rudi Cc: Arjan van de Ven , fbdev , Andrew Morton , Andrea Righi , Krzysztof Helt , Greg Kroah-Hartman , Geert Uytterhoeven , Philippe De Muyter , linux-kernel@vger.kernel.org On Tue, Jul 14, 2009 at 1:43 PM, Ali Gholami Rudi wrote: > Dave Airlie wrote: >> On Tue, Jul 14, 2009 at 2:25 AM, Ali Gholami Rudi wrote= : >> > Arjan van de Ven wrote: >> >> can we turn this around, is there a reason to add them? >> >> or in other words, how / where would these be used ? >> > >> > User-space programs that use framebuffer directly can use them. =A0= I was >> > writing a simple framebuffer virtual terminal (using libfreetype f= or >> > fonts; like fbterm); scrolling and painting boxes would be faster = if >> > there was someway of using hardware accelerated operations. =A0I t= hink >> > other similar programs can benefit, too. >> >> The general opinion is we should keep acceleration in userspace if a= t >> all possible. > > I see. =A0The line between user- and kernel-space for graphic applica= tions > is very blurred to me :-) > >> Not all hw can implement these usefully in the kernel, directfb > > AFAICT, many major ones like intelfb, radeonfb and nv implement them = and > those that can't, use a software implementation. =A0You mean they are > unreliable or that there is little performance improvement because of > the way those operations are implemented in the kernel? Generally newer consumer HW can't implement a simple blit without using= the 3D engine which requires a large amount of state to be sent to the devi= ce. Keeping the state encoding and stuff out of the kernel and in userspace= is generally seen as the right thing to do. >> already does some >> things for this. > > Sometime ago I did try running directfb on a radeon r300 and it faile= d. > I didn't try hard to see what's wrong but I got the impression that > userspace apps are not good at using the hardware directly. directfb has hw accel for different cards, really porting the code out = of the kernel for the cards you are interested in would probably benefit more. Dave.