[PATCH] vgaswitcheroo: Fix error checking in vga_switcheroo_register_audio_client()

[Dan Carpenter]

The "id" variable is an enum and in this context it's treated as an
unsigned int so the error handling can never trigger.  The
->get_client_id() functions do not currently return any errors but
I imagine that if they did, then the intention was to return
VGA_SWITCHEROO_UNKNOWN_ID on error.  Let's check for both negatives
and UNKNOWN_ID so we'll catch it either way.

Reported-by: Su Hui <suhui at nfschina.com>
Closes: https://lore.kernel.org/all/20231026021056.850680-1-suhui@nfschina.com/
Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
---
 drivers/gpu/vga/vga_switcheroo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 18f2c92beff8..216fb208eb31 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 	mutex_lock(&vgasr_mutex);
 	if (vgasr_priv.active) {
 		id = vgasr_priv.handler->get_client_id(vga_dev);
-		if (id < 0) {
+		if ((int)id < 0 || id == VGA_SWITCHEROO_UNKNOWN_ID) {
 			mutex_unlock(&vgasr_mutex);
 			return -EINVAL;
 		}
-- 
2.47.2