Hi Hans, Pls find responses inline. Regards Anand -----Original Message----- From: Jack Wang [mailto:xjtuwjp@xxxxxxxxx] Sent: Monday, July 15, 2013 2:24 PM To: Hans Verkuil Cc: Anand Kumar Santhanam; lindar_liu; linux-scsi@xxxxxxxxxxxxxxx; jinpu.wang@xxxxxxxxxxxxxxxx Subject: Re: The pm80xx driver hangs in 3.10 with the Adaptec 71605H HBA Hi Hans, On 07/14/2013 10:45 AM, Hans Verkuil wrote: > Hi Anand, > > On 07/12/2013 03:14 PM, Anand Kumar Santhanam wrote: >> Hans, >> >> I reviewed the code changes and I did not see major differences >> except for the fact that in adaptec driver we have 64 interrupt >> handlers to handle 64 MSI-X. >> This was optimized in open src driver to use only 1 interrupt handler. >> Can you pls make this change to the open src driver (i.e have >> multiple interrupt handlers for multiple MSI-X) and check? > > I've looked at this more closely, and I wonder whether there isn't a > race condition here. When an interrupt arrives you put the interrupt > vector in pm8001_ha->int_vector, then schedule the tasklet. But what > if two interrupts with different vectors arrive in quick succession > before the tasklet got a chance to run? In that case the tasklet will only see the second vector, not the first. Rather scary. > > I have not actually seen any issues with this, but by definition race > conditions are hard to reproduce and I haven't done any serious > testing with this card. For now I will run with the quick and dirty msi.diff (http://hverkuil.home.xs4all.nl/msi.diff). > > I see two solutions: either use the 64 interrupt handlers as done in > the adaptec driver, or you can change int_vector into a u64 and use it > as a bitmask to record all interrupt vectors that have arrived. Thanks for looking into this, I think second one is what we want, set the bitmask when interrupt arrived and clear it when it's processed. Anand>> Yes. We will go for the second solution. The multiple interrupt/tasklet handlers for MSI-X got rejected by the community and hence We went for the existing approach. I checked with a single controller and I did not observe any issues. Also pls note that the open source driver Supports only one MSI-X for now and this problem will not occur. > > BTW, another difference between the linux kernel driver and the > adaptec version are several of the defines in pm8001_defs.h: e.g. > MPI_QUEUE is 256 in the adaptec driver, while it is 1024 in the kernel driver. There are other differences as well. > Different value may reflect different performance character, but both should works, there is no one for all setting. Anand >> I agree with Jack. I will check on the #defines and get back. > Are all the changes in the kernel correct? I would like to have a > confirmation of that before I am going to trust my data to this driver. > > It clearly hasn't been tested with actual hardware :-( > :_( >> My sincere apologies. I tested the same with single controller and it worked fine. However I messed up when submitting The patches. This was my first open source submission and request you to bear the inconvenience. Thanks, Jack > Regards, > > Hans > -- 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
