Re: [edk2-devel] [PATCH 0/1] Fix XhciDxe Timeouts

["Wu, Hao A" <hao.a.wu@intel.com>]

> -----Original Message-----
> From: Laszlo Ersek <lersek@redhat.com>
> Sent: Wednesday, September 2, 2020 2:49 PM
> To: devel@edk2.groups.io; Wu, Hao A <hao.a.wu@intel.com>;
> patrick.henz@hpe.com
> Cc: Wang, Jian J <jian.j.wang@intel.com>; Ni, Ray <ray.ni@intel.com>; Liming
> Gao (Byosoft address) <gaoliming@byosoft.com.cn>
> Subject: Re: [edk2-devel] [PATCH 0/1] Fix XhciDxe Timeouts
> 
> On 09/02/20 07:08, Wu, Hao A wrote:
> >> -----Original Message-----
> >> From: patrick.henz@hpe.com <patrick.henz@hpe.com>
> >> Sent: Wednesday, September 2, 2020 2:55 AM
> >> To: devel@edk2.groups.io
> >> Cc: henz <patrick.henz@hpe.com>; Wang, Jian J
> >> <jian.j.wang@intel.com>; Wu, Hao A <hao.a.wu@intel.com>; Ni, Ray
> >> <ray.ni@intel.com>
> >> Subject: [PATCH 0/1] Fix XhciDxe Timeouts
> >>
> >> From: henz <patrick.henz@hpe.com>
> >>
> >> Timeouts in the XhciDxe driver are taking longer than expected due to
> >> the timeout loops not accounting for code execution time. As en
> >> example, 5 second timeouts have been observed to take around 36 seconds
> to complete.
> >> Use SetTimer and Create/CheckEvent from Boot Services to determine
> >> when timeout occurred. This patch was tested using forced timeouts
> >> and print statements with QEmu as well as phycial hardware. The
> >> forced timeouts were implemented in code via static variables that
> >> guaranteed a timeout the first time the function with the broken timeout was
> called.
> >>
> >> Example:
> >>
> >> XhcExecTransfer (
> >>   .
> >>   .
> >>  )
> >> {
> >>   .
> >>   .
> >>   static int do_once = 1;  // test line
> >>   .
> >>   .
> >>   do {
> >>     Finished = XhcCheckUrbResult (Xhc, Urb);
> >>     if (do_once) Finished = 0; // test line
> >>     if (Finished) {
> >>       break;
> >>     }
> >>     gBS->Stall (XHC_1_MICROSECOND);
> >>   } while (!EFI_ERROR(TimerStatus) && EFI_ERROR(gBS->CheckEvent
> >> (TimeoutEvent)));
> >>
> >>   do_once = 0; // test line
> >>
> >> Using this forced timeout approach the correct timeouts were observed
> >> on both hardware and in QEmu.
> >>
> >> Similar broken timeout loops have been found in the Uhci and Ehci
> >> drivers. This patch does not fix those issues.
> >
> >
> > Hello Patrick,
> >
> > Besides the comments made by Ray in patch 1, could you help to provide 2
> more patches for UHCI and EHCI drivers as well for complete enhancement?
> > Thanks in advance.
> 
> We're very close to the edk2-stable202008 tag deadline.
> 
> This patch -- which in v2 is going to be a patch series -- is not aiming at the
> stable tag, does it?


Hello Laszlo,

The patch (series) seems more like an enhancement to me. So I think it is not aiming the upcoming tag.

Best Regards,
Hao Wu


> 
> Thanks!
> Laszlo