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authorHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-09-13 02:33:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-13 14:41:52 -0700
commit3aa04f1b07352be89960bddca4db0d5d8c09510c (patch)
treeda1d1862f745989af20f54f25ed53ab726070324 /crypto
parent8275d102f8dbaa4f437f6b03b00d85bfb4e16025 (diff)
atmel_lcdfb: disable LCD and DMA engines when suspending
When suspending the system with atmel_lcdfb enabled, I sometimes see this: atmel_lcdfb atmel_lcdfb.0: FIFO underflow 0x10 Which can be explained by the fact that we're not stopping the LCD controller and its DMA engine when suspending, we're just gating the clocks to them. There's another potential issue which may be harder to trigger but much more nasty: If we gate the clocks at _just_ the right moment, e.g. when the DMA engine is doing a bus transaction, we may cause the DMA engine to violate the system bus protocol and cause a lockup. Avoid these issues by shutting down the LCD controller before entering suspend (and restarting it when resuming). This prevents the underrun from happening in the first place, and prevents whatever nastiness is happening when the bus clock stops in the middle of a DMA transfer. Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'crypto')
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