Re: [PATCH v3 1/2] libahci: Add support to handle HOST_IRQ_STAT as edge trigger latch.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Tejun,

On Mon, May 4, 2015 at 11:56 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello,
>
> On Mon, May 04, 2015 at 10:13:11PM +0530, Suman Tripathi wrote:
>> AFAIK clearing host_irq_stat means we have handled port interrupts .
>> Now for our case we still have interrupts left because it didn't get
>> detected on
>> first ahci_port_intr.  So you  mean to handle that residual irq in the
>> next cycle (i mean next call intr handler ) ??
>
> Heh, I think we're talking past each other.  For level triggered IRQs,
> the latched IRQ bits should be cleared after handling the events;
> otherwise, the latched bits are gonna get set immediately as the
> events are still pending.  Also, this doesn't lose any events as
> they're level triggered latches - if any event is pending, the IRQ is
> gonna be raised again.
>
> Edge triggered latches are the other way around.  You should clear the
> latches before actually handling and clearing the events.  The pending
> events won't trigger the latches again as it's edge-triggered and the
> events which happens after this irq handling starts won't get lost as
> they'll be latched for the next round.

Yeah it's very simple. The clearing of irq_stat needs to move up.
That's it. tried and it worked. Thanks a lot !!
Just a quick question : Why edge trigger handling is not yet present
in libahci yet? I mean no one has used it yet ??

>
> Thanks.
>
> --
> tejun



-- 
Thanks,
with regards,
Suman Tripathi
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]
  Powered by Linux