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Re: [PATCH] serial driver PMC MSP71xx, kernel linux-mips.git mast er

To: Marc St-Jean <>
Subject: Re: [PATCH] serial driver PMC MSP71xx, kernel linux-mips.git mast er
From: Sergei Shtylyov <>
Date: Mon, 12 Feb 2007 20:56:25 +0300
In-reply-to: <>
Organization: MontaVista Software Inc.
Original-recipient: rfc822;
References: <>
User-agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803

Marc St-Jean wrote:

>> > Fourth attempt at the serial driver patch for the PMC-Sierra MSP71xx

I think you need to submit your patch to Andrew Morton since it requires a patch from his tree.

OK, will do.

In fact, since the serial drivers are not maintained anymore, this seems the only option.

>> > +                     /* The DesignWare APB UART has an Busy Detect
>> > +                      * interrupt meaning an LCR write attempt
>>occured while the
>> > +                      * UART was busy. The interrupt must be cleared
>>by reading
>> > +                      * the UART status register (USR) and the LCR
>>re-written. */
>> > +                     unsigned int status;
>> > + status = *(volatile u32 *)up->port.private_data;
>> > +                     serial_out(up, UART_LCR, up->lcr);
>> > +
>> > +                     handled = 1;
>> > +
>> > +                     end = NULL;
>> >               } else if (end == NULL)
>> >                       end = l;

>> >       return 0;

>>    Still, shouldn't you be doing this in serial8250_timeout()

> No, the serial8250_timeout is for issue 1 at the top, this is for
> issue 2.

   It's for lost interrupts, IIUC. They use anothe timeout handler for the

This issue (2) is a completely new type of interrupt generated but the
DesignWare APB uart, it has nothing to do with lost interrupts.

   Yeah, I just thought that the lost interrupts might be a "generic" issue.

>>What IRQ numbers this UART is using, BTW?

> For the ports on the device they are 27 and 42. Is there any significance
> that I'm not aware of?

Yeah, IRQ0 is treated as no IRQ by 8250, and in this case it falls back to using serial8250_timeout() to handle "interrupts".

Good to know. It won't be affecting us then.

   This may be overriden anyway...

>>    Oops, your mailer went and did it again. :-)

> I'm completely giving up on Thunderbird,unless someone can point out

   Ypu should have long ago. :-)

> the specific internal configuration items which needs a kick!

   Only the attachments will work in the Mozilla kind mailer, AFAIK.
The last patch looked OK at last. :-)

The attachemnents appear to be MIME which is a no-no according the

The text/plain type attachments seem to be acceptable for the most maintainers. This Mozilla can do, at least. :-)

linux FAQ at I guess I'll stick with /bin/mail.


WBR, Sergei

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