2019-12-05 12:09:59

by Xiongfeng Wang

Subject: [PATCH] tty: omap-serial: remove set but unused variable

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 <[email protected]>
Signed-off-by: Xiongfeng Wang <[email protected]>
---
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);

up->port.icount.rx++;
flag = TTY_NORMAL;
--
1.7.12.4

2019-12-05 12:15:01

by Greg Kroah-Hartman

Subject: Re: [PATCH] tty: omap-serial: remove set but unused variable

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 <[email protected]>
> Signed-off-by: Xiongfeng Wang <[email protected]>
> ---
> 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'?

2019-12-05 12:31:45

by Xiongfeng Wang

Subject: Re: [PATCH] tty: omap-serial: remove set but unused variable

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 <[email protected]>
>> Signed-off-by: Xiongfeng Wang <[email protected]>
>> ---
>> 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'.

Thanks,
Xiongfeng

>
>
> .
>

2019-12-05 12:40:44

by Jiri Slaby

Subject: Re: [PATCH] tty: omap-serial: remove set but unused variable

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 <[email protected]>
>>> Signed-off-by: Xiongfeng Wang <[email protected]>
>>> ---
>>> 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 <[email protected]>
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

2019-12-06 07:12:19

by Xiongfeng Wang

Subject: Re: [PATCH] tty: omap-serial: remove set but unused variable

On 2019/12/5 20:39, Jiri Slaby wrote:
> 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 <[email protected]>
>>>> Signed-off-by: Xiongfeng Wang <[email protected]>
>>>> ---
>>>> 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 <[email protected]>
> 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 a lot. I will add it in the comment and send another version.

Thanks,
Xiongfeng

>
> thanks,
>

2019-12-06 07:40:08

by Xiongfeng Wang

Subject: Re: [PATCH] tty: omap-serial: remove set but unused variable

On 2019/12/5 20:39, Jiri Slaby wrote:
> 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 <[email protected]>
>>>> Signed-off-by: Xiongfeng Wang <[email protected]>
>>>> ---
>>>> 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 <[email protected]>
> 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 a lot. I will add it in the comment and send another version.

Thanks,
Xiongfeng

> thanks,
>