On Mon, Apr 23, 2012 at 7:57 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > * Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> [120423 07:22]: >> On Fri, Apr 20, 2012 at 03:22:33PM -0700, Tony Lindgren wrote: >> > * Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> [120418 03:14]: >> > > Using coherent DMA memory with the OMAP DMA engine results in >> > > unpredictable behaviour due to memory ordering issues; as things stand, >> > > there is no guarantee that data written to coherent DMA memory will be >> > > visible to the DMA hardware. >> > > >> > > This is because the OMAP dma_write() accessor contains no barriers, >> > > necessary on ARMv6 and above. The effect of this can be seen in comments >> > > in the OMAP serial driver, which incorrectly talks about cache flushing >> > > for the coherent DMA stuff. >> > > >> > > Rather than adding barriers to the accessors, add it in the DMA support >> > > code just before we enable DMA, and just after we disable DMA. This >> > > avoids having barriers for every DMA register access. >> > > >> > > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> >> > >> > Acked-by: Tony Lindgren <tony@xxxxxxxxxxx> >> >> Would you like me to push this upstream on my next -rc push (with a >> stable tag?) > > Yes sounds good to me. > FWIW, Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
