On Thu, Oct 09, 2014 at 11:09:00AM +0900, Yoshihiro Shimoda wrote: > This patch fixes a race condition about a list of shdma-base driver. > If we don't apply this patch, a dma slave driver (especially a usb > peripheral driver) may not be able to start the transfer. > > If a dma slave driver has a callback, __ld_cleanup() will call > the callback before this driver removes the list. After the callback, > since the return value of __ld_cleanup() is not zero, > shdma_chan_ld_cleanup() calls __ld_cleanup() again. And, __ld_clean() > will removes the list. > > At this time, if a dma slave driver calls dmaengine_submit() before > this driver removes the list, this driver will set schan->pm_state > to SHDMA_PM_PENDING in shdma_tx_submit(). And then, even if a dma > slave driver calls dma_async_issue_pending(), this driver don't > start the transfer because the schan->pm_state is SHDMA_PM_PENDING > in shdma_issue_pending(). > > So, this patch adds a new condition in __ld_clean() to check if the > schan->pm_state is SHDMA_PM_PENDING or not. Applied, thanks -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
