Hi, On Thu, Mar 28, 2024 at 03:42:40PM +0000, Diogo Ivo wrote: > On Wed, Mar 27, 2024 at 05:06:38PM +0100, Christian Ehrhardt wrote: > > On Wed, Mar 27, 2024 at 12:39:04PM +0000, Diogo Ivo wrote: > > > This fixes a problem with some LG Gram laptops where the PPM sometimes > > > notifies the OPM with the Connector Change Indicator field set in the > > > CCI after an ACK_CC_CI command is sent,causing the UCSI stack to check > > > the connector status indefinitely since the EVENT_PENDING bit is already > > > cleared. This causes an interrupt storm and an artificial high load on > > > these platforms. > > > > If the PPM does this for a connector change ACK_CC_CI command it is > > IMHO violating the spec (unless there is a _new_ event). > > Yes, the problem is exactly that the PPM in these laptops is really not > conformant with the spec and moving the command change ACK_CC_CI to the > end circumvented the problems in the PPM. If [1] is the way to go then > we need some sort of quirk for these devices and I'll have to dig > deeper. Just to make this clear: This is not my call to make. > > When I saw this type of loops the connector change indicator was set > > in response to an ACK_CC_CI command for a command (sent by a different > > thread for a different connector) between clearing the EVENT_PENDING > > bit and acquiring the PPM lock. > > > > Can you test if the changes that already are in usb-linus are > > sufficient to fix your issues? > > I am seeing these problems when addressing one connector only, so other > threads for other connectors do not play a role here. I have tested the > latest usb-linus with and without your early ack patch set [1] on top > and the issue is still not fixed. There are legitimate reaons why the connector change indicator is set in response to a command: - If the condition was reported previously it is sticky until cleared. - Something else changed on the connector. For a more complicated device that I have here, there are five different connector change events after plugging it in. I'd like to understand why you run into a loop here. Printing the completed command (if any) and the CCI in ucsi_acpi_notify() and the details of the connector status in ucsi_handle_connector_change() could shed some light on this. > [1]: https://lore.kernel.org/linux-usb/20240327224554.1772525-1-lk@xxxxxxx/ Best regards Christian
