From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <199910071913.VAA00361@piglet.cpu.lu> Date: Thu, 7 Oct 1999 21:13:03 +0200 (CEST) From: Michel Lanners Reply-To: mlan@cpu.lu Subject: Re: busmaster/latency for video To: Geert.Uytterhoeven@sonycom.com cc: ran@krazynet.com, linuxppc-dev@lists.linuxppc.org In-Reply-To: MIME-Version: 1.0 Content-Type: TEXT/plain; CHARSET=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On 7 Oct, this message from Geert Uytterhoeven echoed through cyberspace: > On Thu, 7 Oct 1999, Michel Lanners wrote: >> On 6 Oct, this message from Ryan Nielsen echoed through cyberspace: >> > PCI_COMMAND_MASTER is not enabled and latency = 0 for the ultimate rez video card, and pci_write_config_* >> > do not change them. latency = 32 and mastering is enabled for all the other cards in the machine, >> > >> > should they be enabled ? >> >> That probably means the card doesn't support them. >> >> Normal graphic cards have no need for mastership. Only those with video >> inputs need it, in order to transfer video data into the framebuffer >> without CPU help. > > Many recent graphics chips to support bus mastering, especially the AGP ones. Ah, but in that case Apple's OF should enable bus mastering. If I read well between the lines of Apple's docs, OF should set a few default parameters on all PCI devices, among which bus mastering. I'm not sure about latency, though... Michel ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email mlan@cpu.lu | http://www.cpu.lu/~mlan | Learn Always. " ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/