On Thu, Dec 22, 2022 at 02:26:44AM +0000, Matthias Kaehlcke wrote:
The primary task of the onboard_usb_hub driver is to control the power of an onboard USB hub. The driver gets the regulator from the device tree property "vdd-supply" of the hub's DT node. Some boards have device tree nodes for USB hubs supported by this driver, but don't specify a "vdd-supply". This is not an error per se, it just means that the onboard hub driver can't be used for these hubs, so don't create platform devices for such nodes.
This change doesn't completely fix the reported regression. It should fix it for the RPi 3 B Plus and boards with similar hub configurations (compatible DT nodes without "vdd-supply"), boards that actually use the onboard hub driver could still be impacted by the race conditions discussed in that thread. Not creating the platform devices for nodes without "vdd-supply" is the right thing to do, independently from the race condition, which will be fixed in future patch.
Fixes: 8bc063641ceb ("usb: misc: Add onboard_usb_hub driver") Link: https://lore.kernel.org/r/d04bcc45-3471-4417-b30b-5cf9880d785d@i2se.com/ Reported-by: Stefan Wahren stefan.wahren@i2se.com Signed-off-by: Matthias Kaehlcke mka@chromium.org
Changes in v2:
- don't create platform devices when "vdd-supply" is missing, rather than returning an error from _find_onboard_hub()
- check for "vdd-supply" not "vdd" (Johan)
- updated subject and commit message
- added 'Link' tag (regzbot)
drivers/usb/misc/onboard_usb_hub_pdevs.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
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This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.
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