From: Jiri Slaby <[email protected]>
With virtual machines like qemu, it's pretty common to see "too much
work for irq4" messages nowadays. This happens when a bunch of output
is printed on the emulated serial console. This is caused by too low
PASS_LIMIT. When ISR loops more than the limit, it spits the message.
I've been using a kernel with doubled the limit and I couldn't see no
problems. Maybe it's time to get rid of the message now?
Signed-off-by: Jiri Slaby <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
---
drivers/tty/serial/8250.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 54482d7..ae477c8 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -81,7 +81,7 @@ static unsigned int skip_txen_test; /* force skip of txen test at init time */
#define DEBUG_INTR(fmt...) do { } while (0)
#endif
-#define PASS_LIMIT 256
+#define PASS_LIMIT 512
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
--
1.7.5.3
On Sun, 5 Jun 2011 22:51:49 +0200
Jiri Slaby <[email protected]> wrote:
> From: Jiri Slaby <[email protected]>
>
> With virtual machines like qemu, it's pretty common to see "too much
> work for irq4" messages nowadays. This happens when a bunch of output
> is printed on the emulated serial console. This is caused by too low
> PASS_LIMIT. When ISR loops more than the limit, it spits the message.
>
> I've been using a kernel with doubled the limit and I couldn't see no
> problems. Maybe it's time to get rid of the message now?
We need a limit to deal with hangs caused by misconfiguration /
mis-detection on ISA ports in particular but we can certainly bump the
limit to handle poor emulations.
On 06/06/2011 02:09 PM, Alan Cox wrote:
> On Sun, 5 Jun 2011 22:51:49 +0200
> Jiri Slaby <[email protected]> wrote:
>
>> From: Jiri Slaby <[email protected]>
>>
>> With virtual machines like qemu, it's pretty common to see "too much
>> work for irq4" messages nowadays. This happens when a bunch of output
>> is printed on the emulated serial console. This is caused by too low
>> PASS_LIMIT. When ISR loops more than the limit, it spits the message.
>>
>> I've been using a kernel with doubled the limit and I couldn't see no
>> problems. Maybe it's time to get rid of the message now?
>
> We need a limit to deal with hangs caused by misconfiguration /
> mis-detection on ISA ports in particular but we can certainly bump the
> limit to handle poor emulations.
Yeah, I meant it that way (get rid of the message by bumping the limit
-- this patch).
thanks,
--
js
suse labs