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Subject:
linux framebuffer vs. linear video driver ???
From: Steven Scholz ####@####.#### Date: 30 Aug 2004 14:56:30 +0100 Message-Id: <41333209.5030809@imc-berlin.de> Hi there, Has onyone expierence in programming microwindows video driver? I wonder if it would be faster to use a dedicated linear video driver instead of the linux framebuffer device (/dev/fb0). Are there other reasons not to use the linux framebuffer? I noticed the file drivers/fblin4sa1100.c. Is it use in addition to /dev/fb0 or instead of? Thanks a million! -- Steven Scholz | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject:
Re: [nanogui] linux framebuffer vs. linear video driver ???
From: "Greg Haerr" ####@####.#### Date: 12 Sep 2004 23:54:31 +0100 Message-Id: <0c1d01c4991b$25a98590$3eba46a6@winXP> : I wonder if it would be faster to use a dedicated linear video driver : instead of the linux framebuffer device (/dev/fb0). Generally, it's a lot faster to use the linux fb device, since you only have to write memory for the graphics to appear, versus having to twiddle I/O space, etc. For instance, the standard VGA driver (non-memory mapped) is considerably more complex. : : Are there other reasons not to use the linux framebuffer? Only if your OS doesn't support it, then one of the more general libraries is generally used. : : I noticed the file drivers/fblin4sa1100.c. Is it use in addition to /dev/fb0 : or instead of? The drivers/fblin{1,2,4,8,16,24,32} drivers are all included in the standard Microwindows build. When Microwindows first starts up, it queries the kernel for the bits per pixel (BPP) that the framebuffer requires, and then loads in function pointers that use one of the above specific linear fb drivers. The fblin4sa100.c is a replacement driver for the standard fblin4.c driver. IIRC, it is a nibble-swapped version, compatible with a certain controller documented in the file header. The drivers/Makefile would be modified to include this driver. Regards, Greg | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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