Re: [RFC] Fix stuck UCSI controller on DELL

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

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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,

-- 
heikki

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diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
index 6bbf490ac401..7e8b1fcfa024 100644
--- a/drivers/usb/typec/ucsi/ucsi_acpi.c
+++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
@@ -113,18 +113,44 @@ ucsi_zenbook_read(struct ucsi *ucsi, unsigned int offset, void *val, size_t val_
 	return 0;
 }
 
-static const struct ucsi_operations ucsi_zenbook_ops = {
-	.read = ucsi_zenbook_read,
-	.sync_write = ucsi_acpi_sync_write,
-	.async_write = ucsi_acpi_async_write
-};
+static int ucsi_dell_sync_write(struct ucsi *ucsi, unsigned int offset,
+				const void *val, size_t val_len)
+{
+	u64 ctrl = *(u64 *)val;
+	int ret;
+
+	ret = ucsi_acpi_sync_write(ucsi, offset, val, val_len);
+	if (ret && (ctrl & (UCSI_ACK_CC_CI | UCSI_ACK_CONNECTOR_CHANGE))) {
+		ctrl= UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE;
+
+		dev_dbg(ucsi->dev->parent, "%s: ACK failed\n", __func__);
+		ret = ucsi_acpi_sync_write(ucsi, UCSI_CONTROL, &ctrl, sizeof(ctrl));
+	}
 
-static const struct dmi_system_id zenbook_dmi_id[] = {
+	return ret;
+}
+
+static const struct dmi_system_id ucsi_acpi_quirks[] = {
 	{
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 			DMI_MATCH(DMI_PRODUCT_NAME, "ZenBook UX325UA_UM325UA"),
 		},
+		.driver_data = &(struct ucsi_operations) {
+			.read = ucsi_zenbook_read,
+			.sync_write = ucsi_acpi_sync_write,
+			.async_write = ucsi_acpi_async_write
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+		},
+		.driver_data = &(struct ucsi_operations) {
+			.read = ucsi_acpi_read,
+			.sync_write = ucsi_dell_sync_write,
+			.async_write = ucsi_acpi_async_write
+		},
 	},
 	{ }
 };
@@ -151,6 +177,7 @@ static int ucsi_acpi_probe(struct platform_device *pdev)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 	const struct ucsi_operations *ops = &ucsi_acpi_ops;
+	const struct dmi_system_id *id;
 	struct ucsi_acpi *ua;
 	struct resource *res;
 	acpi_status status;
@@ -180,8 +207,9 @@ static int ucsi_acpi_probe(struct platform_device *pdev)
 	init_completion(&ua->complete);
 	ua->dev = &pdev->dev;
 
-	if (dmi_check_system(zenbook_dmi_id))
-		ops = &ucsi_zenbook_ops;
+	id = dmi_first_match(ucsi_acpi_quirks);
+	if (id)
+		ops = id->driver_data;
 
 	ua->ucsi = ucsi_create(&pdev->dev, ops);
 	if (IS_ERR(ua->ucsi))