Uart2 can't work well after the system goto standby and then resume at csr primaII platform

Uart2 can't work well after the system goto standby and then resume at csr primaII platform

[Guoqing Liu]

Daer Sir,
　　 I'm very sorry to trouble you.
     Recently I found the uart2 at csr primaII platform can't work
well after the system  goto standby and then resume.

My test environment is as follows：
     kernel:   3.10.16
     cpu:  csr primaII

 My test process is as follows :
   1> create a thread ,looped transmit data via uart2 every 3s.
   2>primaII goto  standby mode.
   3>primaII　goto  resume.
   4>capture the data at uart2 tx pin by the logic analyzer. you will
found  the data is error.
    　for example when looped send a test frame  : 5A A5 05 FA 1A 00 00
00 05 E2 A3 3A AA 55 77
        you will got : 5A A5 1A 00 00 00 05 E2 A3 3A AA 55 5C E0 77
or  5A A5 05 00 00 00 05 E2 A3 3A AA 55 77 E8 8B
        the result is not fixed.

 I also tried some tests  as follows:
   1> looped send data and do not goto  standby, the result is right.
   2> disable the uart2 dma at prima2.dtsi, the result is right.
   3> when the frame length is 4*n, the result is right. (for example
16, 20,24)

I also add some log at sirfsoc_uart.c:
  print the xmit buffer at  sirfsoc_uart_pio_rx_chars and
sirfsoc_uart_tx_with_dma.
  I found the data is right at uart driver. I also found that the
wrong data is  transmitted by the dma.


Thank you.
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Re: Uart2 can't work well after the system goto standby and then resume at csr primaII platform

[Greg KH]

On Wed, Nov 26, 2014 at 02:17:06PM +0800, Guoqing Liu wrote:
> Daer Sir,
> 　　 I'm very sorry to trouble you.
>      Recently I found the uart2 at csr primaII platform can't work
> well after the system  goto standby and then resume.
> 
> My test environment is as follows：
>      kernel:   3.10.16

That is a very old and obsolete kernel version.  If a vendor is forcing
you to stick to that version, please ask them for support as there's
nothing that we can to do help here, sorry.

Now if you can duplicate this on the 3.17 kernel release, that's a
different story...

good luck,

greg k-h
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Re: Uart2 can't work well after the system goto standby and then resume at csr primaII platform

[Guoqing Liu]

On Thu, Nov 27, 2014 at 2:43 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Wed, Nov 26, 2014 at 02:17:06PM +0800, Guoqing Liu wrote:
>> Daer Sir,
>>　　  I'm very sorry to trouble you.
>>      Recently I found the uart2 at csr primaII platform can't work
>> well after the system  goto standby and then resume.
>>
>> My test environment is as follows：
>>      kernel:   3.10.16
>
> That is a very old and obsolete kernel version.  If a vendor is forcing
> you to stick to that version, please ask them for support as there's
> nothing that we can to do help here, sorry.
>
> Now if you can duplicate this on the 3.17 kernel release, that's a
> different story...
>
> good luck,
>
> greg k-h


Dear Greg
    Thank you very much for your reply.
        I am a newbie to lkml. So I hope you do not mind. :)
　　　Ｉ will try it and feedback as soon as possible.


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