On 2016/4/1 17:58, Andy Shevchenko wrote:
> On Fri, 2016-04-01 at 17:06 +0800, Kefeng Wang wrote:
>> Commit cdcea058e510("serial: 8250_dw: Avoid serial_outx code
>> duplicate
>> with new dw8250_check_lcr()") introduce a wrong logic when write val
>> to
>> LCR reg. When CONFIG_64BIT enabled, __raw_writeq is used
>> unconditionally.
>>
>> But for !PORT_OCTEON, we better to use coincident write func.
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
>> ---
>>
>> We met following calltrace twice, if the change is not necessary,
>> correct me,
>> and any advice will be appreciated, thanks.
>
> So, does this fix you issue? If it does than perhaps you need to Cc
> stable@ and put Fixes tag as well.
We only met this issue twice, for now it is ok, and I will do more
test with this patch.
>
>> --- a/drivers/tty/serial/8250/8250_dw.c
>> +++ b/drivers/tty/serial/8250/8250_dw.c
>> @@ -104,15 +104,16 @@ static void dw8250_check_lcr(struct uart_port
>> *p, int value)
>> dw8250_force_idle(p);
>>
>> #ifdef CONFIG_64BIT
>> - __raw_writeq(value & 0xff, offset);
>> -#else
>> + if (p->type == PORT_OCTEON)
>> + __raw_writeq(value & 0xff, offset);
>> + else
>> +#endif
>
> You may also get rid of this one, like
>
> if (IS_ENABLED(CONFIG_64BIT) && p->type == PORT_OCTEON)
> ...
> else if
> ...
Agree.
>
>> if (p->iotype == UPIO_MEM32)
>> writel(value, offset);
>> else if (p->iotype == UPIO_MEM32BE)
>> iowrite32be(value, offset);
>> else
>> writeb(value, offset);
>> -#endif
>> }
>> /*
>> * FIXME: this deadlocks if port->lock is already held
>
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