atmel_lcdfb: LCDC startup fix
authorAnti Sullin <anti.sullin@artecdesign.ee>
Thu, 29 Nov 2007 00:21:40 +0000 (16:21 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 29 Nov 2007 17:24:53 +0000 (09:24 -0800)
commite593f070b40887dc0415646a4c0720eb8630c722
tree15c7213d85f345602b5a67d7e71c4416b649e6e7
parent2868f89fc43d16441a90714d4676089bdfc4255a
atmel_lcdfb: LCDC startup fix

This patch adds an additional loop, that delays turning off the DMA
until the LCDC core has been turned off. This prevents the picture
to be shifted some random length when the kernel re-initializes
the LCDC.

Without this patch, the LCDC keeps running for some small time after the
PWRCON:LCD_PWR has been cleared ; the FIFO suffers an underrun and on
re-starting the LCDC the FIFO data stays shifted.

This behavior has been seen and fixed on AT91SAM9261-EK and two custom
AT91SAM9261 boards, all of them having different LCD panels.

Thanks a lot to Anti Sullin for submitting this patch (long
time ago).

Signed-off-by: Anti Sullin <anti.sullin@artecdesign.ee>
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/video/atmel_lcdfb.c