From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mikhail Zolotaryov <lebon@faust.net.ua>
Cc: mporter@kernel.crashing.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PPC4xx UART0 (8250) problem
Date: Sat, 07 Apr 2007 15:12:36 +1000 [thread overview]
Message-ID: <1175922756.7407.46.camel@localhost.localdomain> (raw)
In-Reply-To: <46171C50.3020104@faust.net.ua>
On Sat, 2007-04-07 at 07:21 +0300, Mikhail Zolotaryov wrote:
> On PPC4xx embedded we often have UART0 on IRQ0 but 8250 UART driver
> uses IRQ0 as "no irq" hack. It's suggested that platforms with UART
> on IRQ0 will redefine is_real_interrupt(irq) macro but 8250 code
> anyway overrides that. As the result, serial line on UART0 works
> on polling-way and we have character loss on high baud rates.
>
> In patch I added check if UART0 is on IRQ0, if so we define
> is_real_interrupt macro to be 1 (true). Also, check if
> is_real_interrupt macro is already defined added to 8250 UART
> driver.
This is an old problem. The proper fix is already implemented for
arch/powerpc and consist of having virtual irq numbers (which helps for
many other things anyway).
Support for 4xx platforms in arch/powerpc is starting to get in, pop on
linuxppc-dev@ozlabs.org where the patches are being posted and you are
welcome to give a hand porting more platforms over :-)
Ben.
next prev parent reply other threads:[~2007-04-07 5:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-07 4:21 [PATCH] PPC4xx UART0 (8250) problem Mikhail Zolotaryov
2007-04-07 5:12 ` Benjamin Herrenschmidt [this message]
2007-04-07 8:41 ` Mikhail Zolotaryov
-- strict thread matches above, loose matches on Subject: below --
2007-04-06 15:11 Mikhail Zolotaryov
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