Hi! On Mon, 19 Mar 2012 08:52:24 +0100 Stanislaw Gruszka <sgruszka@xxxxxxxxxx> wrote: > > > + if (rt2800usb_txstatus_pending(rt2x00dev) && > > > + test_and_set_bit(TX_STATUS_READING, &rt2x00dev->flags)) > > > > I would put a bang before that test_and... > I don't understand what you mean, perhaps you could post a patch > or provide code snipset here, so I could comment. If I understand correctly, status should be read again if there are pending entries and no one else has set TX_STATUS_READING yet. In that case return value of test_and_set_bit should be negated. I might be missing something though. > > > + while (!kfifo_is_empty(&rt2x00dev->txstatus_fifo) || > > > + rt2800usb_txstatus_timeout(rt2x00dev)) { > > > > > > - rt2800usb_txdone_nostatus(rt2x00dev); > > > + rt2800usb_txdone(rt2x00dev); > > > > > > - /* > > > - * The hw may delay sending the packet after DMA complete > > > - * if the medium is busy, thus the TX_STA_FIFO entry is > > > - * also delayed -> use a timer to retrieve it. > > > - */ > > > - if (rt2800usb_txstatus_pending(rt2x00dev)) > > > - mod_timer(&rt2x00dev->txstatus_timer, jiffies + msecs_to_jiffies(2)); > > > + rt2800usb_txdone_nostatus(rt2x00dev); > > > + > > > + /* > > > + * The hw may delay sending the packet after DMA complete > > > + * if the medium is busy, thus the TX_STA_FIFO entry is > > > + * also delayed -> use a timer to retrieve it. > > > + */ > > > + if (rt2800usb_txstatus_pending(rt2x00dev)) > > > + rt2800usb_async_read_tx_status(rt2x00dev); > > > > How is it possible that this call will ever start the timer? The > > reading "thread" won't exit if rt2800usb_txstatus_pending returns true > > and every dma_done will schedule reading itself. > > I do not understand your objection here too. If rt2800usb_txstatus_pending() > will return true and if TX_STATUS_READING bit is not set, we will run hrtimer > to read status after 500 micro seconds. We exit the loop if kfifo is empty > and no entry timed out waiting to get corresponding TX status. Yes, I don't mean that this code is wrong. I just think that rt2800usb_async_read_tx_status have no chance of actually going past TX_STATUS_READING check. If every dma_done schedules reading and reading stops only when all pending entries have their statuses then call to rt2800usb_async_read_tx_status after we processed statuses is excessive. All that said, I haven't tested this hypothesis and may be completely wrong (again). Also I _don't_ mean that this call should be removed, just wanted to me sure I understand everything correctly ;-) -- Kuba -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html