On 07.03.2024 10:38, Alexandra Winter wrote:
> The IO subsystem expects a driver to retry a ccw_device_start, when the
> subsequent interrupt response block (irb) contains a deferred
> condition code 1.
>
> Symptoms before this commit:
> On the read channel we always trigger the next read anyhow, so no
> different behaviour here.
> On the write channel we may experience timeout errors, because the
> expected reply will never be received without the retry.
> Other callers of qeth_send_control_data() may wrongly assume that the ccw
> was successful, which may cause problems later.
>
> Note that since
> commit 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
> and
> commit 5ef1dc40ffa6 ("s390/cio: fix invalid -EBUSY on ccw_device_start")
> deferred CC1s are more likely to occur. See the commit message of the
> latter for more background information.
>
> Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
> Reference-ID: LTC205042
> Signed-off-by: Alexandra Winter <wintera@xxxxxxxxxxxxx>
Acked-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
--
Peter Oberparleiter
Linux on IBM Z Development - IBM Germany R&D
