On Wed, 2015-09-30 at 09:52 -0400, Peter Hurley wrote: > [ + Andy Shevchenko ] > > On 09/30/2015 08:46 AM, Frederic Danis wrote: > > This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb. > > Hi Frederic, > > It's customary to mail the commit author in patches which revert > their work. > > > This commit prevents from sending "big" file using Bluetooth. > > When sending a lot of data quickly through the Bluetooth interface, > > and > > after a variable amount of data sent, transfer fails with error: > > kernel: [ 415.247453] Bluetooth: hci0 hardware error 0x00 > > Hmmm, was there any other information regarding why this happened? Frederic informed us privately about this issue. I tried to hunt the root cause but mostly (there was one observation but apparently seems it is not related to this issue) nothing looks wrong. > Eg., did the driver mistakenly re-order i/o (DMA occurred after PIO)? I have few tracing dumps which Frederic provides to me, but I couldn't see such a problem. Maybe I missed it. My commit 9119fba0cfed introduces interleaved IO (DMA/PIO) which makes it like DMA -> PIO -> DMA -> ... > Or, might there be some race condition in the dmaengine driver on > this > platform? There is [1] might be a clue, though I don't think it's directly related. [1] http://www.spinics.net/lists/linux-spi/msg01151.html The change prevents interleaved DMA/PIO IO. > > Regards, > Peter Hurley > > > Found on T100TA. > > > > After reverting this commit, send works fine for any file size. > > > > Signed-off-by: Frederic Danis <frederic.danis@xxxxxxxxxxxxxxx> > > --- > > drivers/tty/serial/8250/8250_dma.c | 4 ---- > > 1 file changed, 4 deletions(-) > > > > diff --git a/drivers/tty/serial/8250/8250_dma.c > > b/drivers/tty/serial/8250/8250_dma.c > > index 21d01a4..e508939 100644 > > --- a/drivers/tty/serial/8250/8250_dma.c > > +++ b/drivers/tty/serial/8250/8250_dma.c > > @@ -80,10 +80,6 @@ int serial8250_tx_dma(struct uart_8250_port *p) > > return 0; > > > > dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, > > UART_XMIT_SIZE); > > - if (dma->tx_size < p->port.fifosize) { > > - ret = -EINVAL; > > - goto err; > > - } > > > > desc = dmaengine_prep_slave_single(dma->txchan, > > dma->tx_addr + xmit > > ->tail, > > > -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
