Re: [PATCH 0/2] Disable SS instances in park mode for SC7180/ SC7280

[Krishna Kurapati PSSNV]

On 5/31/2024 7:47 PM, Doug Anderson wrote:
> Hi,
>
> On Fri, May 31, 2024 at 5:33 AM Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> wrote:
> > On 30.05.2024 3:34 PM, Doug Anderson wrote:
> > > Hi,
> > >
> > > On Thu, May 30, 2024 at 1:26 AM Krishna Kurapati
> > > <quic_kriskura@xxxxxxxxxxx> wrote:
> > > > When working in host mode, in certain conditions, when the USB
> > > > host controller is stressed, there is a HC died warning that comes up.
> > > > Fix this up by disabling SS instances in park mode for SC7280 and SC7180.
> > > >
> > > > Krishna Kurapati (2):
> > > >    arm64: dts: qcom: sc7180: Disable SS instances in park mode
> > > >    arm64: dts: qcom: sc7280: Disable SS instances in park mode
> > > >
> > > >   arch/arm64/boot/dts/qcom/sc7180.dtsi | 1 +
> > > >   arch/arm64/boot/dts/qcom/sc7280.dtsi | 1 +
> > > >   2 files changed, 2 insertions(+)
> > >
> > > FWIW, the test case I used to reproduce this:
> > >
> > > 1. Plug in a USB dock w/ Ethernet
> > > 2. Plug a USB 3 SD card reader into the dock.
> > > 3. Use lsusb -t to confirm both Ethernet and card reader are on USB3.
> > > 4. From a shell, run for i in $(seq 5); do dd if=/dev/sdb of=/dev/null
> > > bs=4M; done to read from the card reader.
> > > 5. At the same time, stress the Internet. If you've got a very fast
> > > Internet connection then running Google's "Internet speed test" did
> > > it, but I could also reproduce by just running this from a PC
> > > connected to the same network as my DUT: ssh ${DUT} "dd of=/dev/null"
> > > < /dev/zero
> > >
> > > I would also note that, though I personally reproduced this on sc7180
> > > and sc7280 boards and thus Krishna posted the patch for those boards,
> > > there's no reason to believe that this problem doesn't affect all of
> > > Qualcomm's SoCs. It would be nice if someone at Qualcomm could post a
> > > followup patch fixing this everywhere.
> >
> > Right, this sounds like a more widespread issue
> >
> > That said, I couldn't reproduce it on SC8280XP / X13s (which does NOT mean
> > 8280 isn't affected). My setup was:
> >
> > - USB3 5GB/s hub plugged into one of the side USBs
> >    - on-hub 1 Gb /s network hub connected straight to my router with a
> >      600 / 60 Mbps link, spamming speedtest-cli and dd-over-ssh
> >    - M.2 SSD connected over a USB adapter, nearing 280 MB/s speeds (the
> >      adapter isn't particularly speedy)
> >
> > So it stands to reason that it might not have been enough to trigger it.
>
> In my case I wasn't using anything nearly as fast as a M.2 SSD. I was
> just using a normal USB3 SD card reader. That being said, multiple
> people at Qualcomm were able to replicate the issue without lots of
> back and forth, so I'd guess that the problem isn't that sensitive to
> the exact storage device. I will also note that it's not sensitive to
> the exact network device as I replicated it with two Ethernet adapters
> with very different chipsets.
>
> My only guess is that somehow SC8280XP is faster and that changes the
> timing of how it handles interrupts. I guess you could try capping
> your cpufreq in sysfs and see if that makes a difference in
> reproducing. ;-) ...or maybe somehow SC8280XP has a newer version of
> the IP where they've fixed this?
>
> It would be interesting if someone with a SDM845 dragonboard could try
> replicating since that seems highly likely to reproduce, at least.

Hi Konrad, Doug,

 Usually on downstream we set this quirk only for all Gen-1 targets 
(not particularly for this testcase) but to avoid these kind of 
controller going dead issues. I can filter out the gen-1 targets (other 
than sc7280/sc7180) and send a separate series to add this quirk in all 
of them.

Regards,
Krishna,