Re: Re: [Dri-devel] Rage128 and Radeon patches
flat view
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2003-08-14 22:04:19
On Thu, 2003-08-14 at 18:00, Jon Smirl wrote:
quoted hunk ↗ jump to hunk
--- Benjamin Herrenschmidt <benh@kernel.crashing.org>wrote:quoted
This is a problem. We also parse it to find the DFP EDID and/or flat panel informations, do that work with the real ROM ? I don't know much about x86 BIOSes, but at least for the DFP EDID, I suppose that one is read in RAM by the BIOS, not in the ROM...On x86 machines low RAM contains a copy of the ROM, now you are getting a pointer to the real ROM. The contents are identical. The only difference is that you need to use the readb()/readw()/etc macros to read it. On the x86 readb() does nothing, but on other platforms it will trigger a PCI read cycle. This plus side to this is that you can use multiple video cards.
Well... Again, this has to be verified in real life, but my understanding is that the BIOS code, once it has probed the DFP flat panel, will put the EDID data in RAM somewhere within the copy of the BIOS, which is where we then find it... The best thing would still be, of course, to implement full DDC probing in radeonfb like XFree does. This has been on my todolist for a while now, but I lack time. Ben. ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01