The patch titled
serial: fix UART_BUG_TXEN test
has been removed from the -mm tree. Its filename is
serial-fix-uart_bug_txen-test.patch
This patch was dropped because it is obsolete
------------------------------------------------------
Subject: serial: fix UART_BUG_TXEN test
From: Gerd Hoffmann <kraxel@xxxxxxx>
There is a bug in the UART_BUG_TXEN test: It gives false positives in case
the UART_IER_THRI bit is set. Fixed by explicitly clearing the UART_IER
register first.
It may trigger with an active serial console as serial console writes set
the UART_IER_THRI bit.
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
[akpm: previously nacked, but the problem remains unresolved]
Russell King <rmk@xxxxxxxxxxxxxxxx> wrote:
> On Sun, Jun 25, 2006 at 10:07:03AM +0100, Russell King wrote:
> > On Sun, Jun 25, 2006 at 01:51:22AM -0700, akpm@xxxxxxxx wrote:
> > >
> > > From: Gerd Hoffmann <kraxel@xxxxxxx>
> > >
> > > There is a bug in the UART_BUG_TXEN test: It gives false positives in case
> > > the UART_IER_THRI bit is set. Fixed by explicitly clearing the UART_IER
> > > register first.
> > >
> > > It may trigger with an active serial console as serial console writes set
> > > the UART_IER_THRI bit.
> > >
> > > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxx>
> > > Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
> > >
> > > [akpm: previously nacked, but the problem remains unresolved]
> >
> > It may remain unresolved, but since _NO ONE_ has responded to my requests
> > to re-test with later kernels (or maybe they have and they haven't sent
> > me anything) it's still NAKed.
> >
> > We've fundamentally changed the preconditions which _were_ causing the
> > original problem. It _requires_ a re-checking by someone who had the
> > problem.
>
> So you understand why I'm saying this - the original reason for adding
> this was because the serial console write _incorrectly_ set the transmit
> enable irrespective of whether it should be set or not. That was buggy
> in itself, and has been resolved.
>
> The serial console write no longer sets the transmit enable bit, and as
> such:
>
> > > It may trigger with an active serial console as serial console writes set
> > > the UART_IER_THRI bit.
>
> is no longer true. Which is the specified reason for this patch to exist.
>
> That means that either this patch has not been re-tested on a later
> kernel, or that there's some /other/ reason for this test mis-firing.
> Given that the reports came in _only_ when the THRI enable bit to the
> serial console path, I strongly suspect the former to be the case.
>
> And as such, until there's some feedback on re-testing 2.6.17 without
> this patch applied, and a report saying that it still doesn't work,
> this patch should not go anywhere. On the grounds we've fixed the
> _original_ cause of the problem.
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/serial/8250.c | 1 +
1 file changed, 1 insertion(+)
diff -puN drivers/serial/8250.c~serial-fix-uart_bug_txen-test drivers/serial/8250.c
--- a/drivers/serial/8250.c~serial-fix-uart_bug_txen-test
+++ a/drivers/serial/8250.c
@@ -1772,6 +1772,7 @@ static int serial8250_startup(struct uar
* Do a quick test to see if we receive an
* interrupt when we enable the TX irq.
*/
+ serial_outp(up, UART_IER, 0);
serial_outp(up, UART_IER, UART_IER_THRI);
lsr = serial_in(up, UART_LSR);
iir = serial_in(up, UART_IIR);
_
Patches currently in -mm which might be from kraxel@xxxxxxx are
origin.patch
serial-fix-uart_bug_txen-test.patch
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