Hi Wesley,

On Tue, 21 Sept 2021 at 02:44, Wesley Cheng [off-list ref] wrote:

Hi Amit,

On 9/20/2021 1:45 PM, Amit Pundir wrote:

quoted

Hi Wesley, All,

I see a reboot loop on Xiaomi Pocophone F1 (sdm845) with TX FIFO
resize patches which landed in v5.15-rc1. Upstream commit cefdd52fa045
"usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default" to
be specific, which switched on this feature by default.

At times the phone crashes into the fastboot mode after the reboot
loop, but mostly end up booting to UI after a while. This is what it
looks like https://people.linaro.org/~amit.pundir/beryllium-userdebug/PXL_20210920_162749483.mp4.

I believe Android will attempt a number of bootup sequences and if it
fails, it falls back to fastboot mode.  Are there any available logs you
might be able to collect to see where the issue is?

It is a stock phone with no UART access, so I can't get early crash
logs unless I'm booted up to adb shell. I can try getting some info
using pstore-ramoops but warm reset support for sdm845 was not
upstreamed when I tried using that the last time.

quoted

PocoF1 does support TX fifo resizing as I can see that in the
downstream dts. So maybe it is the tx-fifo-max-num which need to be
adjusted for the device? I couldn't find the tx-fifo-max-num
equivalent in the downstream tree though
https://github.com/MiCode/Xiaomi_Kernel_OpenSource/tree/dipper-q-oss/

I assume that you've already confirmed reverting that change resolves
the constant reboots?

Yes reverting that change resolves the reboot loop issue. Speaking of
which, since no other platform seem to be running into this issue and
"tx-fifo-max-num" property is apparently not at fault either, is it
reasonable to skip adding "tx-fifo-resize" property for PocoF1 using
of_machine_is_compatible("xiaomi,beryllium") as a workaround?

quoted

Curious if you had any ideas what might be going wrong? For now I'll
keep digging around tx-fifo-max-num, but I figured I'd ask just in
case it's obvious to you.

The tx-fifo-max-num parameter should still be set to 6 for SDM845, which
would be the same for more recent targets as well.

Ack.

Regards,
Amit Pundir

Thanks
Wesley Cheng

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