Re: [PATCH 2/3] serial: 8250_omap: check how many bytes were injected

2015-08-26 Thread Sekhar Nori
On Wednesday 26 August 2015 06:14 PM, Peter Hurley wrote:
> On 08/14/2015 12:01 PM, Sebastian Andrzej Siewior wrote:
>> The function tty_insert_flip_string() returns an int and as such it
>> might fail. So the result is that I kindly asked to insert 48 bytes and
>> the function only insterted 32.
>> I have no idea what to do with the remaining 16 so I think dropping them
>> is the only option. I also increase the buf_overrun counter so userpace
>> has a clue that we lost bytes.
> 
> No objection to the patch but I'm curious whether this is something you've
> actually observed and under what circumstances.

This was observed while doing a UART internal loopback test at 3Mbaud on
TI's DRA7 EVM.

Thanks,
Sekhar

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Re: [PATCH 2/3] serial: 8250_omap: check how many bytes were injected

2015-08-26 Thread Peter Hurley
On 08/14/2015 12:01 PM, Sebastian Andrzej Siewior wrote:
> The function tty_insert_flip_string() returns an int and as such it
> might fail. So the result is that I kindly asked to insert 48 bytes and
> the function only insterted 32.
> I have no idea what to do with the remaining 16 so I think dropping them
> is the only option. I also increase the buf_overrun counter so userpace
> has a clue that we lost bytes.

No objection to the patch but I'm curious whether this is something you've
actually observed and under what circumstances.

Regards,
Peter Hurley


> Cc: Greg Kroah-Hartman 
> Signed-off-by: Sebastian Andrzej Siewior 
> ---
>  drivers/tty/serial/8250/8250_omap.c | 7 +--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_omap.c 
> b/drivers/tty/serial/8250/8250_omap.c
> index 2ac63c8bd946..933f7ef2c004 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -738,6 +738,7 @@ static void __dma_rx_do_complete(struct uart_8250_port 
> *p, bool error)
>   struct dma_tx_state state;
>   int count;
>   unsigned long   flags;
> + int ret;
>  
>   dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
>   dma->rx_size, DMA_FROM_DEVICE);
> @@ -753,8 +754,10 @@ static void __dma_rx_do_complete(struct uart_8250_port 
> *p, bool error)
>  
>   count = dma->rx_size - state.residue;
>  
> - tty_insert_flip_string(tty_port, dma->rx_buf, count);
> - p->port.icount.rx += count;
> + ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
> +
> + p->port.icount.rx += ret;
> + p->port.icount.buf_overrun += count - ret;
>  unlock:
>   spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
>  
> 

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Re: [PATCH 2/3] serial: 8250_omap: check how many bytes were injected

2015-08-26 Thread Sekhar Nori
On Friday 14 August 2015 09:31 PM, Sebastian Andrzej Siewior wrote:
> The function tty_insert_flip_string() returns an int and as such it
> might fail. So the result is that I kindly asked to insert 48 bytes and
> the function only insterted 32.
> I have no idea what to do with the remaining 16 so I think dropping them
> is the only option. I also increase the buf_overrun counter so userpace
> has a clue that we lost bytes.
> 
> Cc: Greg Kroah-Hartman 
> Signed-off-by: Sebastian Andrzej Siewior 

Tested with wilink BT module on TI's DRA7 EVM.

Tested-by: Sekhar Nori 

Thanks,
Sekhar

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