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SubjectRe: [PATCH] tty: omap-serial: remove set but unused variable
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On 05. 12. 19, 13:30, Xiongfeng Wang wrote:
>
>
> On 2019/12/5 20:13, Greg KH wrote:
>> On Thu, Dec 05, 2019 at 08:04:36PM +0800, Xiongfeng Wang wrote:
>>> Fix the following warning:
>>> drivers/tty/serial/omap-serial.c: In function serial_omap_rlsi:
>>> drivers/tty/serial/omap-serial.c:496:16: warning: variable ch set but not used [-Wunused-but-set-variable]
>>>
>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
>>> ---
>>> drivers/tty/serial/omap-serial.c | 3 +--
>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
>>> index 6420ae5..54ee3ae 100644
>>> --- a/drivers/tty/serial/omap-serial.c
>>> +++ b/drivers/tty/serial/omap-serial.c
>>> @@ -493,10 +493,9 @@ static unsigned int check_modem_status(struct uart_omap_port *up)
>>> static void serial_omap_rlsi(struct uart_omap_port *up, unsigned int lsr)
>>> {
>>> unsigned int flag;
>>> - unsigned char ch = 0;
>>>
>>> if (likely(lsr & UART_LSR_DR))
>>> - ch = serial_in(up, UART_RX);
>>> + serial_in(up, UART_RX);
>>
>> Shouldn't you be doing something with 'ch'?
>
> Sorry, my original thought is trying not to modify the existing logic.
> I will look into the mechanism to see if I need to check 'ch'.

The change looks in fact correct, see:
commit 9a12fcf8b1543c99ffcec3d61db86f0dea52dc9d
Author: Shubhrajyoti D <shubhrajyoti@ti.com>
Date: Fri Sep 21 20:07:19 2012 +0530

serial: omap: fix the reciever line error case

It also says: "This is recommended in the interrupt reset method in the
table 23-246 of the omap4 TRM."

The character read is erroneous and should be apparently dropped. But
you should add a comment about it, though.

thanks,
--
js
suse labs

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