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Commit f1aafdcd authored by Tomi Valkeinen's avatar Tomi Valkeinen
Browse files

OMAP: DSS2: make 50ms bug-fix sleep optional 



For some unknown reason we may get SYNC_LOST errors from the display
subsystem at initialization time if we don't sleep before resetting the
DSS. See the source (dss.c) for more comments.

However, 50ms is quite long time to sleep, and with some configurations
the SYNC_LOST may never happen, so this patch creates a Kconfig option
to disable the sleep.

Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
parent d792eecd

drivers/video/omap2/dss/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -125,4 +125,15 @@ config OMAP2_DSS_MIN_FCK_PER_PCK 
	  Max FCK is 173MHz, so this doesn't work if your PCK

	  is very high.



config OMAP2_DSS_SLEEP_BEFORE_RESET

	bool "Sleep 50ms before DSS reset"

	default y

	help

	  For some unknown reason we may get SYNC_LOST errors from the display

	  subsystem at initialization time if we don't sleep before resetting

	  the DSS. See the source (dss.c) for more comments.



	  However, 50ms is quite long time to sleep, and with some

	  configurations the SYNC_LOST may never happen, so the sleep can

	  be disabled here.

endif

drivers/video/omap2/dss/dss.c

+5 −0
Original line number Diff line number Diff line
@@ -665,13 +665,18 @@ static int dss_init(void) 
	 * the kernel resets it */

	omap_writel(omap_readl(0x48050440) & ~0x3, 0x48050440);



#ifdef CONFIG_OMAP2_DSS_SLEEP_BEFORE_RESET

	/* We need to wait here a bit, otherwise we sometimes start to

	 * get synclost errors, and after that only power cycle will

	 * restore DSS functionality. I have no idea why this happens.

	 * And we have to wait _before_ resetting the DSS, but after

	 * enabling clocks.

	 *

	 * This bug was at least present on OMAP3430. It's unknown

	 * if it happens on OMAP2 or OMAP3630.

	 */

	msleep(50);

#endif



	_omap_dss_reset();