usb: typec: ucsi: cancel pending work on system suspend

commit 7c4a234 upstream.

On a Dell XPS 13 9360 (BIOS 2.21.0), entering system suspend (deep/S3)
races a pending UCSI connector-change worker against the ACPI EC teardown.
The worker evaluates the UCSI _DSM (GET_CONNECTOR_STATUS), whose AML
accesses the Embedded Controller. By that point the ACPI EC has already
been stopped for suspend, so the EC address space handler rejects the
access with AE_BAD_PARAMETER, aborting the AML and failing the connector
query:

    [22314.689495] ACPI: EC: interrupt blocked
    [22314.711981] ACPI: PM: Preparing to enter system sleep state S3
    [22314.743260] ACPI: EC: event blocked
    [22314.743265] ACPI: EC: EC stopped
    [22314.743267] ACPI: PM: Saving platform NVS memory
    [22314.744241] ACPI Error: AE_BAD_PARAMETER, Returned by Handler for [EmbeddedControl] (20260408/evregion-303)
    [22314.744432] ACPI Error: Aborting method \_SB.PCI0.LPCB.ECDV.ECW1 due to previous error (AE_BAD_PARAMETER) (20260408/psparse-543)
    [22314.744673] ACPI Error: Aborting method \ECWB due to previous error (AE_BAD_PARAMETER) (20260408/psparse-543)
    [22314.745201] ACPI Error: Aborting method \_SB.UBTC._DSM due to previous error (AE_BAD_PARAMETER) (20260408/psparse-543)
    [22314.745394] ACPI: \_SB_.UBTC: failed to evaluate _DSM c298836f-a47c-e411-ad36-631042b5008f rev:1 func:1 (0x1001)
    [22314.745414] ucsi_acpi USBC000:00: ucsi_acpi_dsm: failed to evaluate _DSM 1
    [22314.745424] ucsi_acpi USBC000:00: ucsi_handle_connector_change: GET_CONNECTOR_STATUS failed (-5)

ucsi_acpi implements a resume callback but no suspend callback, so nothing
cancels the connector-change work before the firmware/EC is torn down.

Add a `ucsi_suspend()` core helper that cancels the pending init and
connector-change work, and wire it into ucsi_acpi's PM ops. The connector
state is re-read on resume by `ucsi_resume()`, so cancelling the work loses
nothing.

Fixes: 4e3a502 ("usb: typec: ucsi: acpi: Implement resume callback")
Cc: stable <stable@kernel.org>
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Assisted-by: Claude Opus 4.8
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260703110738.8457-2-pmenzel@molgen.mpg.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: paulmenzel

drivers/usb/typec/ucsi/ucsi.c

@@ -1918,6 +1918,26 @@ static void ucsi_resume_work(struct work_struct *work)
 	}
 }
 
+int ucsi_suspend(struct ucsi *ucsi)
+{
+	int i;
+
+	/*
+	 * Cancel pending work so it cannot access the firmware after the ACPI
+	 * EC is stopped for suspend; state is re-read on resume.
+	 */
+	cancel_delayed_work_sync(&ucsi->work);
+
+	if (!ucsi->connector)
+		return 0;
+
+	for (i = 0; i < ucsi->cap.num_connectors; i++)
+		cancel_work_sync(&ucsi->connector[i].work);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ucsi_suspend);
+
 int ucsi_resume(struct ucsi *ucsi)
 {
 	if (ucsi->connector)

drivers/usb/typec/ucsi/ucsi.h

@@ -551,6 +551,7 @@ int ucsi_send_command(struct ucsi *ucsi, u64 command,
 		      void *retval, size_t size);
 
 void ucsi_altmode_update_active(struct ucsi_connector *con);
+int ucsi_suspend(struct ucsi *ucsi);
 int ucsi_resume(struct ucsi *ucsi);
 
 void ucsi_notify_common(struct ucsi *ucsi, u32 cci);

drivers/usb/typec/ucsi/ucsi_acpi.c

@@ -245,14 +245,22 @@ static void ucsi_acpi_remove(struct platform_device *pdev)
 				   ucsi_acpi_notify);
 }
 
+static int ucsi_acpi_suspend(struct device *dev)
+{
+	struct ucsi_acpi *ua = dev_get_drvdata(dev);
+
+	return ucsi_suspend(ua->ucsi);
+}
+
 static int ucsi_acpi_resume(struct device *dev)
 {
 	struct ucsi_acpi *ua = dev_get_drvdata(dev);
 
 	return ucsi_resume(ua->ucsi);
 }
 
-static DEFINE_SIMPLE_DEV_PM_OPS(ucsi_acpi_pm_ops, NULL, ucsi_acpi_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(ucsi_acpi_pm_ops, ucsi_acpi_suspend,
+				ucsi_acpi_resume);
 
 static const struct acpi_device_id ucsi_acpi_match[] = {
 	{ "PNP0CA0", 0 },