SCPI regressions in v4.15-rc1 on Amlogic SoCs.

[Kevin Hilman]

On Thu, Nov 30, 2017 at 11:08 PM, Heiner Kallweit <hkallweit1 at gmail.com> wrote:
> Am 01.12.2017 um 01:21 schrieb Kevin Hilman:
>> Hi Sudeep,
>>
>> There's been a pretty major regression in v4.15-rc1 compared to v4.15
>> in SCPI causing warning splats on amlogic SoCs when cpufreq starts up
>> and tries to set the OPP for the first time[1].
>>
> Thanks for the report. Strange enough, it works perfectly fine on my
> Odroid-C2, see below log part from latest next kernel.

There are alot more amlogic SoCs out there that should've been tested
with this change, and you didn't Cc linux-amlogic or ask for more help
testing.  Now we're in a position to have major regressions on most
amlogic boards for v4.15.

> Your log seems to indicate that due to deferred probing something is
> not done in the right order.
> Can you bisect the issue? I'd assume that it's commit 931cf0c53e69
> ("firmware: arm_scpi: pre-populate dvfs info in scpi_probe").

I do not currnetly have the time to bisect this, and we're in the
"fixes" phase of the merge window so there is urgency.

I would much rather see these patches reverted, and actually tested on
affected platforms before they make it into mainline.

Sudeep, any chance of reverting these while we're still in the -rc phase?

Thanks,

Kevin

> Rgds, Heiner
>
> [    0.034293] soc soc0: Amlogic Meson GXBB (S905) Revision 1f:0 (c:1) Detected
> [    0.036666] c81004c0.serial: ttyAML0 at MMIO 0xc81004c0 (irq = 13, base_baud = 1500000) is a meson_uart
> [    0.606914] console [ttyAML0] enabled
> [    0.615031] loop: module loaded
> [    0.616117] meson-gx-mmc d0074000.mmc: allocated mmc-pwrseq
> [    0.643406] ledtrig-cpu: registered to indicate activity on CPUs
> [    0.644047] meson-sm: secure-monitor enabled
> [    0.648156] hidraw: raw HID events driver (C) Jiri Kosina
> [    0.653572] platform-mhu c883c404.mailbox: Platform MHU Mailbox registered
> [    0.660439] NET: Registered protocol family 17
> [    0.665031] registered taskstats version 1
> [    0.668689] Loading compiled-in X.509 certificates
> [    0.678049] meson-gx-mmc d0072000.mmc: Got CD GPIO
> [    0.712946] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> [    0.715600] cpu cpu0: bL_cpufreq_init: CPU 0 initialized
> [    0.719245] arm_big_little: bL_cpufreq_register: Registered platform driver: scpi
> [    0.727344] mmc0: new HS400 MMC card at address 0001
> [    0.729179] hctosys: unable to open rtc device (rtc0)
> [    0.729355] USB_OTG_PWR: disabling
> [    0.729358] TFLASH_VDD: disabling
> [    0.729361] TF_IO: disabling
> [    0.747230] mmcblk0: mmc0:0001 DJNB4R 116 GiB
> [    0.752588] mmcblk0boot0: mmc0:0001 DJNB4R partition 1 4.00 MiB
> [    0.757220] mmcblk0boot1: mmc0:0001 DJNB4R partition 2 4.00 MiB
> [    0.762274] mmcblk0rpmb: mmc0:0001 DJNB4R partition 3 4.00 MiB, chardev (249:0)
> [    0.770243]  mmcblk0: p1
> [    0.781732] EXT4-fs (mmcblk0p1): mounted filesystem with ordered data mode. Opts: (null)
>
>
>> I ran out of time to narrow it down further since there have been
>> quite a few changes since v4.14, but simply reverting
>> drivers/firmware/arm_scpi.c to its v4.14 state gets things working
>> again.
>>
>> This has been happening for awhile, and we should've caught it sooner
>> in kernelCI.org, however this warning splat still allows the kernel to
>> finish booting, so it still resulted in a PASS for the boot test.
>> That combined with the fact that we've been tracking some other
>> regressions, we didn't notice it until now.
>>
>> Also, is this the expected result for the pre-1.0 firmware:
>>
>>     scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
>>
>> Kevin
>>
>> [1] Here are a few boot logs from v4.15-rc1 with the splat:
>>
>> https://storage.kernelci.org/mainline/master/v4.15-rc1/arm64/defconfig/lab-baylibre-seattle/boot-meson-gxl-s905x-khadas-vim.html
>>
>> https://storage.kernelci.org/mainline/master/v4.15-rc1/arm64/defconfig/lab-baylibre-seattle/boot-meson-gxbb-p200.html
>>
>> https://storage.kernelci.org/mainline/master/v4.15-rc1/arm64/defconfig/lab-baylibre-seattle/boot-meson-gxl-s905d-p230.html
>>
>