diff mbox series

[RFC] Fix stuck UCSI controller on DELL

Message ID 20240103100635.57099-1-lk@c--e.de
State New
Headers show
Series [RFC] Fix stuck UCSI controller on DELL | expand

Commit Message

Christian A. Ehrhardt Jan. 3, 2024, 10:06 a.m. UTC 
I have a DELL Latitude 5431 where typec only works somewhat.
After the first plug/unplug event the PPM seems to be stuck and
commands end with a timeout (GET_CONNECTOR_STATUS failed (-110)).

This patch fixes it for me but according to my reading it is in
violation of the UCSI spec. On the other hand searching through
the net it appears that many DELL models seem to have timeout problems
with UCSI.

Do we want some kind of quirk here? There does not seem to be a quirk
framework for this part of the code, yet. Or is it ok to just send the
additional ACK in all cases and hope that the PPM will do the right
thing?

     regards   Christian

Comments

Heikki Krogerus Jan. 4, 2024, 11:59 a.m. UTC | #1 
Hi Christian,

On Wed, Jan 03, 2024 at 11:06:35AM +0100, Christian A. Ehrhardt wrote:
> I have a DELL Latitude 5431 where typec only works somewhat.
> After the first plug/unplug event the PPM seems to be stuck and
> commands end with a timeout (GET_CONNECTOR_STATUS failed (-110)).
> 
> This patch fixes it for me but according to my reading it is in
> violation of the UCSI spec. On the other hand searching through
> the net it appears that many DELL models seem to have timeout problems
> with UCSI.
> 
> Do we want some kind of quirk here? There does not seem to be a quirk
> framework for this part of the code, yet. Or is it ok to just send the
> additional ACK in all cases and hope that the PPM will do the right
> thing?

We can use DMI quirks. Something like the attached diff (not tested).

thanks,
diff mbox series

Patch

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 61b64558f96c..65098a454f63 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -53,7 +53,10 @@  static int ucsi_acknowledge_connector_change(struct ucsi *ucsi)
 	ctrl = UCSI_ACK_CC_CI;
 	ctrl |= UCSI_ACK_CONNECTOR_CHANGE;
 
-	return ucsi->ops->sync_write(ucsi, UCSI_CONTROL, &ctrl, sizeof(ctrl));
+	if (ucsi->ops->sync_write(ucsi, UCSI_CONTROL, &ctrl, sizeof(ctrl)))
+		pr_err("ACK FAILED\n");
+
+	return ucsi_acknowledge_command(ucsi);
 }
 
 static int ucsi_exec_command(struct ucsi *ucsi, u64 command);