On Tue, 21 Sept 2021 at 13:00, Wesley Cheng [off-list ref] wrote:

Hi Amit,

On 9/21/2021 12:04 AM, Amit Pundir wrote:

quoted

Hi Wesley,

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

quoted

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.

I see, can we maybe avoid the actual resizing by commenting out the
following writel() calls, but let the fifo resize logic calculate the EPs?

void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc)
{
...
                /* Don't change TXFRAMNUM on usb31 version */
                size = DWC3_IP_IS(DWC3) ? 0 :
                        dwc3_readl(dwc->regs, DWC3_GTXFIFOSIZ(num >> 1)) &
                                   DWC31_GTXFIFOSIZ_TXFRAMNUM;
                /* Comment the dwc3_writel() */
                //dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(num >> 1), size);

and

static int dwc3_gadget_resize_tx_fifos(struct dwc3_ep *dep)
{
...
        /* Comment the dwc3_writel() */
        //dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(dep->number >> 1), fifo_size);
        dwc->num_ep_resized++;

Those 2 writel() would be the one that actually programs the TXFIFO
register.  I hope when commented out, no resize should actually happen
anymore.

With this, hopefully we can get some logs from the device at least :)

I can boot fine with above 2 writel() removed but I don't see EP
counts being printed in the log anywhere and the only relevant
message in dmesg I see is this:

    Duplicate name in dwc3@a600000, renamed to "tx-fifo-resize#1"

which is interesting because I don't see tx-fifo-resize property being
set by any of the upstream sdm845 or relevant dtsi files.

quoted

quoted

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?

Since SDM845 does technically support txfifo resize downstream, let me
see if I can figure out what is different on this particular device
after getting the logs.

Thanks
Wesley Cheng

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