Vinod Koul <vinod.koul@xxxxxxxxx> writes: > On Mon, Mar 28, 2016 at 11:32:24PM +0200, Robert Jarzmik wrote: >> In the current state, upon bus error the driver will spin endlessly, >> relaunching the last tx, which will fail again and again : >> - a bus error happens >> - pxad_chan_handler() is called >> - as PXA_DCSR_STOPSTATE is true, the last non-terminated transaction is >> lauched, which is the one triggering the bus error, as it didn't >> terminate >> - moreover, the STOP interrupt fires a new, as the STOPIRQEN is still >> active >> >> Break this logic by stopping the automatic relaunch of a dma channel >> upon a bus error, even if there are still pending issued requests on it. >> >> As dma_cookie_status() seems unable to return DMA_ERROR in its current >> form, ie. there seems no way to mark a DMA_ERROR on a per-async-tx >> basis, it is chosen in this patch to remember on the channel which >> transaction failed, and report it in pxad_tx_status(). >> >> It's a bit misleading because if T1, T2, T3 and T4 were queued, and T1 >> was completed while T2 causes a bus error, the status of T3 and T4 will >> be reported as DMA_IN_PROGRESS, while the channel is actually stopped. > > No it is not misleading. The subsequent descriptor can be submitted and > continued. But yes you are right on the error reporting part, that is > something we need to add. Ok, fair enough. > So what exactly are you trying to fix/achive here? Euh you mean the first chapter about the "endless spin" is not clear ? This is what I'm trying to fix, the unstoppable endless relauch of a descriptor doomed to make the same bus error over and over again. For the record, I saw this corner case by programming an address hole as destination address ... not very clever I know :) Cheers. -- Robert -- 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
