Some LG Gram laptops report a bogus connector change event after a
GET_PDOS command for the partner's source PDOs, which disappears from
the CCI after acknowledging the command. However, the subsequent
GET_CONNECTOR_STATUS in ucsi_handle_connector_change() still reports
this bogus change in bits 5 and 6, leading to the UCSI core re-checking
the partner's source PDOs and thus to an infinite loop.
Fix this by adding a quirk that signals when a potentially buggy GET_PDOS
command is used, checks the status change report and clears it if it is a
bogus event before sending it to the UCSI core.
[Sending as RFC both to see if this is a good idea and so that more
users can test it to gather all the models affected by this bug.]
Signed-off-by: Diogo Ivo <diogo.ivo@xxxxxxxxxxxxxxxxxx>
---
drivers/usb/typec/ucsi/ucsi_acpi.c | 60 ++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
index 8d112c3edae5..c67607f68b44 100644
--- a/drivers/usb/typec/ucsi/ucsi_acpi.c
+++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
@@ -25,6 +25,7 @@ struct ucsi_acpi {
unsigned long flags;
#define UCSI_ACPI_COMMAND_PENDING 1
#define UCSI_ACPI_ACK_PENDING 2
+#define UCSI_ACPI_CHECK_BOGUS_EVENT 4
guid_t guid;
u64 cmd;
};
@@ -128,6 +129,58 @@ static const struct ucsi_operations ucsi_zenbook_ops = {
.async_write = ucsi_acpi_async_write
};
+static int ucsi_gram_read(struct ucsi *ucsi, unsigned int offset,
+ void *val, size_t val_len)
+{
+ u16 bogus_change = UCSI_CONSTAT_POWER_LEVEL_CHANGE |
+ UCSI_CONSTAT_PDOS_CHANGE;
+ struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
+ struct ucsi_connector_status *status;
+ int ret;
+
+ ret = ucsi_acpi_read(ucsi, offset, val, val_len);
+ if (ret < 0)
+ return ret;
+
+ if (UCSI_COMMAND(ua->cmd) == UCSI_GET_CONNECTOR_STATUS &&
+ ua->flags & UCSI_ACPI_CHECK_BOGUS_EVENT &&
+ offset == UCSI_MESSAGE_IN) {
+ status = (struct ucsi_connector_status *)val;
+
+ /* Clear the bogus change */
+ if (status->change == bogus_change)
+ status->change = 0;
+
+ ua->flags &= ~UCSI_ACPI_CHECK_BOGUS_EVENT;
+ }
+
+ return ret;
+}
+
+static int ucsi_gram_sync_write(struct ucsi *ucsi, unsigned int offset,
+ const void *val, size_t val_len)
+{
+ struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
+ int ret;
+
+ ret = ucsi_acpi_sync_write(ucsi, offset, val, val_len);
+ if (ret < 0)
+ return ret;
+
+ if (UCSI_COMMAND(ua->cmd) == UCSI_GET_PDOS &&
+ ua->cmd & UCSI_GET_PDOS_PARTNER_PDO(1) &&
+ ua->cmd & UCSI_GET_PDOS_SRC_PDOS)
+ ua->flags |= UCSI_ACPI_CHECK_BOGUS_EVENT;
+
+ return ret;
+}
+
+static const struct ucsi_operations ucsi_gram_ops = {
+ .read = ucsi_gram_read,
+ .sync_write = ucsi_gram_sync_write,
+ .async_write = ucsi_acpi_async_write
+};
+
static const struct dmi_system_id ucsi_acpi_quirks[] = {
{
.matches = {
@@ -136,6 +189,13 @@ static const struct dmi_system_id ucsi_acpi_quirks[] = {
},
.driver_data = (void *)&ucsi_zenbook_ops,
},
+ {
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "LG Electronics"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Z90Q"),
+ },
+ .driver_data = (void *)&ucsi_gram_ops,
+ },
{ }
};
--
2.45.0
