On Fri, Aug 28, 2015 at 01:12:19PM +0100, Matt Fleming wrote: > From: Matt Fleming <matt.fleming@xxxxxxxxx> > > The EFI Graphics Output Protocol uses 64-bit frame buffer addresses > but these get truncated to 32-bit by the EFI boot stub when storing > the address in the 'lfb_base' field of 'struct screen_info'. > > Add a 'ext_lfb_base' field for the upper 32-bits of the frame buffer > address and set VIDEO_TYPE_CAPABILITY_64BIT_BASE when the field is > useable. > > It turns out that the reason no one has required this support so far > is that there's actually code in tianocore to "downgrade" PCI > resources that have option ROMs and 64-bit BARS from 64-bit to 32-bit > to cope with legacy option ROMs that can't handle 64-bit addresses. > The upshot is that basically all GOP devices in the wild use a 32-bit > frame buffer address. > > Still, it is possible to build firmware that uses a full 64-bit GOP > frame buffer address. Chad did, which led to him reporting this issue. > > Add support in anticipation of GOP devices using 64-bit addresses more > widely, and so that efifb works out of the box when that happens. > > Reported-by: Chad Page <chad.page@xxxxxxxx> > Cc: Pete Hawkins <pete.hawkins@xxxxxxxx> > Cc: Peter Jones <pjones@xxxxxxxxxx> > Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx> > Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx> Looks good to me. Acked-by: Peter Jones <pjones@xxxxxxxxxx> -- Peter -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html