With CONFIG_PM=y, the omapfb/lcdc device on Amstrad Delta, after initially
starting correctly, breaks with the following error messages:
omapfb omapfb: resetting (status 0xffffff96,reset count 1)
...
omapfb omapfb: resetting (status 0xffffff96,reset count 100)
omapfb omapfb: too many reset attempts, giving up.
Looking closer at this I have found that it had been broken almost 2 years ago
with commit 2418996e3b100114edb2ae110d5d4acb928909d2, PM fixes for OMAP1.
The definite reason for broken omapfb/lcdc behavoiur in PM mode
appeared to be ARM_IDLECT1:IDLIF_ARM (bit 6) put into idle regardless of LCD
DMA possibly running. The bit were set based on return value of the
omap_dma_running() function that did not check for dedicated LCD DMA
channel status. The patch below fixes this.
Created against linux-2.6.32-rc6
Tested on Amstrad Delta
Signed-off-by: Janusz Krzysztofik <jkrzyszt@xxxxxxxxxxxx>
---
Tuesday 03 November 2009 21:10:48 Tony Lindgren wrote:
> * Janusz Krzysztofik <jkrzyszt@xxxxxxxxxxxx> [091103 12:05]:
> > Sorry, I've not checked for new mail before posting this one and missed
> > your acceptance for my idea of fixing all omap1510, not only ams_delta.
> > If there are no more comments, I'll submit v3 with cpu_is_omap1510()
> > replacing machine_is_ams_delta().
>
> Sounds good to me.
>
> Tony
--- linux-2.6.32-rc6/arch/arm/plat-omap/dma.c.orig 2009-11-03 20:37:49.000000000 +0100
+++ linux-2.6.32-rc6/arch/arm/plat-omap/dma.c 2009-11-05 19:30:39.000000000 +0100
@@ -1108,6 +1108,14 @@ int omap_dma_running(void)
{
int lch;
+ /*
+ * On OMAP1510, internal LCD controller will start the transfer
+ * when it gets enabled, so assume DMA running if LCD enabled.
+ */
+ if (cpu_is_omap1510())
+ if (omap_readw(0xfffec000 + 0x00) & (1 << 0))
+ return 1;
+
/* Check if LCD DMA is running */
if (cpu_is_omap16xx())
if (omap_readw(OMAP1610_DMA_LCD_CCR) & OMAP_DMA_CCR_EN)
--
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