45d89a344e
In the dwc3 core, both system and runtime suspend end up calling dwc3_suspend_common(). From there, what happens for the PHYs depends on the USB mode and whether the controller is entering system or runtime suspend. HOST mode: (1) system suspend on a non-wakeup-capable controller The [1] if branch is taken. dwc3_core_exit() is called, which ends up calling phy_power_off() and phy_exit(). Those two functions decrease the PM runtime count at some point, so they will trigger the PHY runtime sleep (assuming the count is right). (2) runtime suspend / system suspend on a wakeup-capable controller The [1] branch is not taken. dwc3_suspend_common() calls phy_pm_runtime_put_sync(). Assuming the ref count is right, the PHY runtime suspend op is called. DEVICE mode: dwc3_core_exit() is called on both runtime and system sleep unless the controller is already runtime suspended. OTG mode: (1) system suspend : dwc3_core_exit() is called (2) runtime suspend : do nothing In host mode, the code seems to make a distinction between 1) runtime sleep / system sleep for wakeup-capable controller, and 2) system sleep for non-wakeup-capable controller, where phy_power_off() and phy_exit() are only called for the latter. This suggests the PHY is not supposed to be in a fully powered-off state for runtime sleep and system sleep for wakeup-capable controller. Moreover, downstream, cfg_ahb_clk only gets disabled for system suspend. The clocks are disabled by phy->set_suspend() [2] which is only called in the system sleep path through dwc3_core_exit() [3]. With that in mind, don't disable the clocks during the femto PHY runtime suspend callback. The clocks will only be disabled during system suspend for non-wakeup-capable controllers, through dwc3_core_exit(). [1] https://elixir.bootlin.com/linux/v6.4/source/drivers/usb/dwc3/core.c#L1988 [2] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/LV.AU.1.2.1.r2-05300-gen3meta.0/drivers/usb/phy/phy-msm-snps-hs.c#L524 [3] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/LV.AU.1.2.1.r2-05300-gen3meta.0/drivers/usb/dwc3/core.c#L1915 Signed-off-by: Adrien Thierry <athierry@redhat.com> Link: https://lore.kernel.org/r/20230629144542.14906-2-athierry@redhat.com Signed-off-by: Vinod Koul <vkoul@kernel.org> |
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| arch | ||
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| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
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| COPYING | ||
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| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.