FB-access-wrapper?

Thomas Winischhofer thomas at winischhofer.net
Thu Jan 13 19:12:42 PST 2005


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As said, I am dealing with a driver for a device that is connected via
USB. All video memory, MMIO and i/o port access has to go over the wire.

Is there any - reasonable (I don't intend to rewrite half of the XAA
code) - way to wrap ALL server functions that directly access video RAM
(apart from using the dead-slow shadow framebuffer)?

I would like to use the accelerators of this device but that's nil if I
can't do that.

The shadow framebuffer works basically, but it due to the packet
overhead, it is really slow. Even an optimized refresharea() function
which transfers all boxes in one chunk (from xmin/ymin to xmax/ymax)
doesn't really help. I still can see lines around menus being drawn etc.
It's the large number of small dirty areas submitted to my refresharea()
what makes it look really bad. Video playback is no problem on the other
hand.

Thanks for any hints,

Thomas

PS: I really wonder how Windows handles this. Using this device with XP
makes it look almost like a real graphics card. I practically don't see
any drawing operations. Windows and menus appear instantly, there is no
visible delay...

- --
Thomas Winischhofer
Vienna/Austria
thomas AT winischhofer DOT net          http://www.winischhofer.net/
twini AT xfree86 DOT org
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