ACPI: fix a regression of ACPI device driver autoloading
commit 3620f2f2f39e7870cf1a4fb2e34063a142f28716 sets the cid of
ACPI video/dock/bay device and leaves the hid empty.
As a result, "modalias" should export the cid for
devices which don't have a hid.
ACPI Video driver is not autoloaded with
commit 3620f2f2f39e7870cf1a4fb2e34063a142f28716 applied.
"cat /sys/.../device:03(acpi video bus)/modalias" shows nothing.
ACPI Video driver is autoloaded after revert that commit.
"cat /sys/.../LNXVIDEO:0x/modalias" shows "acpi:LNXVIDEO:"
ACPI Video driver is autoloaded with commit
3620f2f2f39e7870cf1a4fb2e34063a142f28716 and this patch applied.
"cat /sys/.../device:03(acpi video bus)/modalias"
shows "acpi:LNXVIDEO:"
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 57570ac..e6ce262 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -39,20 +39,26 @@
int size)
{
int len;
+ int count;
- if (!acpi_dev->flags.hardware_id)
+ if (!acpi_dev->flags.hardware_id && !acpi_dev->flags.compatible_ids)
return -ENODEV;
- len = snprintf(modalias, size, "acpi:%s:",
- acpi_dev->pnp.hardware_id);
- if (len < 0 || len >= size)
- return -EINVAL;
+ len = snprintf(modalias, size, "acpi:");
size -= len;
+ if (acpi_dev->flags.hardware_id) {
+ count = snprintf(&modalias[len], size, "%s:",
+ acpi_dev->pnp.hardware_id);
+ if (count < 0 || count >= size)
+ return -EINVAL;
+ len += count;
+ size -= count;
+ }
+
if (acpi_dev->flags.compatible_ids) {
struct acpi_compatible_id_list *cid_list;
int i;
- int count;
cid_list = acpi_dev->pnp.cid_list;
for (i = 0; i < cid_list->count; i++) {