[S390] qdio: 2nd stage retry on SIGA-W busy conditions

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The SIGA-W may return with the busy bit set which means the device was
blocked. The busy loop which retries the SIGA-W for 100us may not be
long enough when running under a heavily loaded hypervisor.

Extend the retry mechanism by adding a longer second stage which retries
the SIGA-W for up to 10s. In difference to the first retry loop the second
stage is using mdelay to stop the cpu between the retries and thereby
avoid additional preassure in on the hypervisor.
If the second stage retry is successfull a device reset is avoided.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

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Jan Glauber 2011-08-03 16:44:17 +02:00 • committed by Heiko Carstens

parent ed8f37370d

commit be8d97a540

2 changed files with 20 additions and 3 deletions

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2

drivers/s390/cio/qdio.h

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21

drivers/s390/cio/qdio_main.c

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