• Niklas Cassel's avatar
    ata: libata-eh: do not thaw the port twice in ata_eh_reset() · 7a3bc2b3
    Niklas Cassel authored
    commit 1e641060 ("libata: clear eh_info on reset completion") added
    a workaround that broke the retry mechanism in ATA EH.
    
    Tejun himself suggested to remove this workaround when it was identified
    to cause additional problems:
    https://lore.kernel.org/linux-ide/20110426135027.GI878@htj.dyndns.org/
    
    He even said:
    "Hmm... it seems I wasn't thinking straight when I added that work around."
    https://lore.kernel.org/linux-ide/20110426155229.GM878@htj.dyndns.org/
    
    While removing the workaround solved the issue, however, the workaround was
    kept to avoid "spurious hotplug events during reset", and instead another
    workaround was added on top of the existing workaround in commit
    8c56cacc ("libata: fix unexpectedly frozen port after ata_eh_reset()").
    
    Because these IRQs happened when the port was frozen, we know that they
    were actually a side effect of PxIS and IS.IPS(x) not being cleared before
    the COMRESET. This is now done in commit 94152042eaa9 ("ata: libahci: clear
    pending interrupt status"), so these workarounds can now be removed.
    
    Since commit 1e641060 ("libata: clear eh_info on reset completion") has
    now been reverted, the ATA EH retry mechanism is functional again, so there
    is once again no need to thaw the port more than once in ata_eh_reset().
    
    This reverts "the workaround on top of the workaround" introduced in commit
    8c56cacc ("libata: fix unexpectedly frozen port after ata_eh_reset()").
    Signed-off-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
    Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
    7a3bc2b3
libata-eh.c 108 KB