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[PATCH 0/2] tty: serial: msm_serial regression and add info message

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  [PATCH 0/2] tty: serial: msm_serial regression and add info message Frank Rowand <frowand.list@gmail.com> - 2016-04-23 19:20 +0200
    [PATCH 2/2] tty: serial: msm_serial add info message Frank Rowand <frowand.list@gmail.com> - 2016-04-23 19:20 +0200
      Re: [PATCH 2/2] tty: serial: msm_serial add info message Stephen Boyd <sboyd@codeaurora.org> - 2016-04-25 22:50 +0200
        Re: [PATCH 2/2] tty: serial: msm_serial add info message Frank Rowand <frowand.list@gmail.com> - 2016-04-25 23:40 +0200
          Re: [PATCH 2/2] tty: serial: msm_serial add info message Stephen Boyd <sboyd@codeaurora.org> - 2016-04-25 23:40 +0200
            Re: [PATCH 2/2] tty: serial: msm_serial add info message Frank Rowand <frowand.list@gmail.com> - 2016-04-26 02:50 +0200

#1385691 — [PATCH 0/2] tty: serial: msm_serial regression and add info message

Commit 3a878c430fd6 ("tty: serial: msm: Add TX DMA support") resulted
in dropped characters and invalid characters in pio mode.  Fix the
problem and add an additional information message that was important
in diagnosing the problem (reporting that DMA mode was not enabled).

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#1385692 — [PATCH 2/2] tty: serial: msm_serial add info message

From: Frank Rowand <frank.rowand@am.sony.com>

Failure to enable DMA by the msm_serial driver is silent.
Add a message to report the failure.

Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
---
 drivers/tty/serial/msm_serial.c |    1 +
 1 file changed, 1 insertion(+)

Index: b/drivers/tty/serial/msm_serial.c
===================================================================
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -170,6 +170,7 @@ rel_tx:
 	dma_release_channel(dma->chan);
 no_tx:
 	memset(dma, 0, sizeof(*dma));
+	dev_info(dev, "msm_serial: DMA not enabled\n");
 }
 
 static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)

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#1386880 — Re: [PATCH 2/2] tty: serial: msm_serial add info message

On 04/23, Frank Rowand wrote:
> From: Frank Rowand <frank.rowand@am.sony.com>
> 
> Failure to enable DMA by the msm_serial driver is silent.
> Add a message to report the failure.
> 
> Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
> ---
>  drivers/tty/serial/msm_serial.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> Index: b/drivers/tty/serial/msm_serial.c
> ===================================================================
> --- a/drivers/tty/serial/msm_serial.c
> +++ b/drivers/tty/serial/msm_serial.c
> @@ -170,6 +170,7 @@ rel_tx:
>  	dma_release_channel(dma->chan);
>  no_tx:
>  	memset(dma, 0, sizeof(*dma));
> +	dev_info(dev, "msm_serial: DMA not enabled\n");
>  }
>  

Wouldn't this print twice for TX and RX channels? I'd prefer we
not print anything when this driver probes, just because it's a
bunch of log spam that we don't really need.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1386917 — Re: [PATCH 2/2] tty: serial: msm_serial add info message

On 4/25/2016 1:48 PM, Stephen Boyd wrote:
> On 04/23, Frank Rowand wrote:
>> From: Frank Rowand <frank.rowand@am.sony.com>
>>
>> Failure to enable DMA by the msm_serial driver is silent.
>> Add a message to report the failure.
>>
>> Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
>> ---
>>  drivers/tty/serial/msm_serial.c |    1 +
>>  1 file changed, 1 insertion(+)
>>
>> Index: b/drivers/tty/serial/msm_serial.c
>> ===================================================================
>> --- a/drivers/tty/serial/msm_serial.c
>> +++ b/drivers/tty/serial/msm_serial.c
>> @@ -170,6 +170,7 @@ rel_tx:
>>  	dma_release_channel(dma->chan);
>>  no_tx:
>>  	memset(dma, 0, sizeof(*dma));
>> +	dev_info(dev, "msm_serial: DMA not enabled\n");
>>  }
>>  
> 
> Wouldn't this print twice for TX and RX channels? I'd prefer we
> not print anything when this driver probes, just because it's a
> bunch of log spam that we don't really need.

This is in msm_request_tx_dma().  I should have made the message
"msm_serial: TX DMA not enabled\n" and added a similar message
to msm_request_rx_dma().

Then it could print twice, once for TX and once for RX. :-)
For my board it would print twice because both requests would
fail for the same reason.

Should I add it to msm_request_rx_dma() also, but make both
locations dev_debug() instead of dev_info()?

-Frank

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#1386918 — Re: [PATCH 2/2] tty: serial: msm_serial add info message

On 04/25, Frank Rowand wrote:
>
> This is in msm_request_tx_dma().  I should have made the message
> "msm_serial: TX DMA not enabled\n" and added a similar message
> to msm_request_rx_dma().
> 
> Then it could print twice, once for TX and once for RX. :-)
> For my board it would print twice because both requests would
> fail for the same reason.

Ah right, the 3 line diff window caught me here.

> 
> Should I add it to msm_request_rx_dma() also, but make both
> locations dev_debug() instead of dev_info()?

Honestly I don't see much point in having this at all. Why does
the user care if DMA is used or not? Don't they just want the
hardware to work? Maybe dev_dbg(), but again, debug junk. I'll
leave it up to you and Greg.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1387037 — Re: [PATCH 2/2] tty: serial: msm_serial add info message

On 4/25/2016 2:35 PM, Stephen Boyd wrote:
> On 04/25, Frank Rowand wrote:
>>
>> This is in msm_request_tx_dma().  I should have made the message
>> "msm_serial: TX DMA not enabled\n" and added a similar message
>> to msm_request_rx_dma().
>>
>> Then it could print twice, once for TX and once for RX. :-)
>> For my board it would print twice because both requests would
>> fail for the same reason.
> 
> Ah right, the 3 line diff window caught me here.
> 
>>
>> Should I add it to msm_request_rx_dma() also, but make both
>> locations dev_debug() instead of dev_info()?
> 
> Honestly I don't see much point in having this at all. Why does
> the user care if DMA is used or not? Don't they just want the
> hardware to work? Maybe dev_dbg(), but again, debug junk. I'll
> leave it up to you and Greg.

If the user doesn't care if DMA is used then why even bother
implementing it in the driver?  :-)

I don't _need_ the messages, I just need the driver to quit
dropping bytes and writing corrupt bytes.  So patch 1 of 2 is
sufficient for my needs.

-Frank

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