On Thu, Oct 02, 2003 at 11:45:28AM -0700, Sottek, Matthew J wrote: >The public driver can reconfigure the amount of RAM just fine up >to 128MB (for 830M and greater) > >The issue you are describing is with mode setting. The driver uses >the vbios to set modes, and the vbios has a preconfigured amount of >RAM that it knows to be available for the framebuffer. This means >that the vbios will only set modes that will fit into the amount >of memory that it reserved at boot time. > >The XFree driver can add to the amount of RAM available to the >driver for pixmaps, back buffers, DMA etc... but it cannot >convince the vbios to set modes that are larger than the boot >time selection which is guaranteed to be available to the display >engine.
The XFree86 driver supports two methods for informing the vbios that the amount of memory available has changed. The first method uses a scratch register, and appears to work for most 830M and older 845G systems. The second method uses a new BIOS call intended precisely for this purpose but it's not clear how many real systems out there have it. >I believe there are independently developed patches floating around >that modify int10's vbios copy at runtime to "educate" the vbios >about the change in framebuffer memory for some systems whose >vbios comes with an undesirable setting. This seems to fill the gap left by the varied availability of the other methods. BTW, on a different by related subject, I got a report last week of an 865G that doesn't appear to support any of the Intel extended vbios functions, including the one that the driver uses to set the refresh rate for modes. David -- David Dawes X-Oz Technologies www.XFree86.org/~dawes www.x-oz.com _______________________________________________ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
