Re: Card's view of framebuffer offset i

On 15 Jul 02 at 4:56, Ville Syrjälä wrote:

On Mon, Jul 15, 2002 at 02:02:14AM +0200, Petr Vandrovec wrote:

quoted

On Sun, Jul 14, 2002 at 04:10:29PM +0300, Ville Syrjälä wrote:

quoted

Is there a way to ge the framebuffer offset to userspace? I hacked
DirectFB to draw to the crtc2 display but currently I've had to hardcode
the framebuffer offset. So I need something I can feed to tmy G400.

In what environment? With matroxfb you have special framebuffer which
is displayed by CRTC2 engine.

quoted

Offset is not explicitly exported, but
if you'll take low 24 bits from fb_start, you'll get offset on
G400/G450/G550 devices.

I don't see such a thing anywhere. Do you mean smem_start? Ok just tried
with (smem_start + offset & 0x1ffffff) and it works for both heads. So
that's actually 25 bits. Maybe I should just use 28 bits to accomodate
larger framebuffers?

No. You must use exactly 25 bits on G400/G450/G550 series, because of
upper 7 bits are random: framebuffer apperture is 32MB on them, and upper
7 bits specify framebuffer position in PCI MMIO address space.
                                                Petr Vandrovec
                                                


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