linux-toradex.git/arch/arc/include/asm/fb.h, branch v4.10 Linux kernel for Apalis and Colibri modules arc: Add our own implementation of fb_pgprotect() 2016-04-07T09:29:09+00:00 Alexey Brodkin Alexey.Brodkin@synopsys.com 2016-03-28T11:36:38+00:00 e5e0a65cd20a7a892a87e6bd73bdc3d83726d725 During mmaping of frame-buffer pages to user-space fb_protect() is called to set proper page settings. In case of ARC we need to mark pages that are mmaped to user as uncached because of 2 reasons: * Huge amount of data if passing through data cache will thrash cache a lot making cache almost useless for other less traffic hungry processes. * Data written by user in FB will be immediately available for hardware (such as PGU etc) without requirements to flush data cache regularly. Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
During mmaping of frame-buffer pages to user-space
fb_protect() is called to set proper page settings.

In case of ARC we need to mark pages that are mmaped to
user as uncached because of 2 reasons:
 * Huge amount of data if passing through data cache will
   thrash cache a lot making cache almost useless for other
   less traffic hungry processes.
 * Data written by user in FB will be immediately available for
   hardware (such as PGU etc) without requirements to flush data
   cache regularly.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>