hi Dan, On Mon, 13 Jul 2020 at 21:37, Dan Robertson <dan@xxxxxxxxxxxxxxx> wrote: > > When testing suspend for another driver I noticed the following warning: > > WARNING: CPU: 1 PID: 5530 at drivers/reset/core.c:355 reset_control_assert+0x184/0x19c > Hardware name: Hardkernel ODROID-N2 (DT) > [..] > pc : reset_control_assert+0x184/0x19c > lr : dwc3_meson_g12a_suspend+0x68/0x7c > [..] > Call trace: > reset_control_assert+0x184/0x19c > dwc3_meson_g12a_suspend+0x68/0x7c > platform_pm_suspend+0x28/0x54 > __device_suspend+0x590/0xabc > dpm_suspend+0x104/0x404 > dpm_suspend_start+0x84/0x1bc > suspend_devices_and_enter+0xc4/0x4fc > > In my limited experience and knowlege it appears that we hit this > because the reset control was switched to shared and the the use > of the reset control was not changed. > > > * Calling reset_control_assert without first calling reset_control_deassert > > * is not allowed on a shared reset control. Calling reset_control_reset is > > * also not allowed on a shared reset control. > > The above snippet from reset_control_get_shared() seems to indicate that > this is due to the use of reset_control_reset() in dwc3_meson_g12a_probe() > and reset_control_deassert is not guaranteed to have been called > before dwc3_meson_g12a_suspend() and reset_control_assert(). > > After some basic tests with the following patch I no longer hit the > warning. Comments and critiques on the patch are welcome. If there is a > reason for the current use of the reset control, I'd love to learn why! > Like I said before, I have not really looked at this driver before and > have verify limited experience with reset controls... Was working on > another driver, hit the warning, and thought I'd take a shot at the > fix :-) > Thanks, I was also looking into this issue So best Fix to this issue is to drop the call of reset_control_assert from dwc3_meson_g12a_suspend and drop the call of reset_control_deassert from dwc3_meson_g12a_resume With these changes we do not see the warning on suspend and resume Can you try this attached patch? Best Regards -Anand
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0001-usb-dwc3-meson-g12a-drop-reset-controller-call-from-.patch
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