On 05/21/2015 05:22 AM, David Cohen wrote:
Hi,
On Wed, May 20, 2015 at 03:33:26PM -0400, Sasha Levin wrote:
ULPI registers it's bus at module_init so if the bus fails to register, the
A minor comment: s/it's/its/
module will fail to load and all will be well in the world.
However, if the ULPI code is built-in rather than a module, the bus
initialization may fail but we'd still try to register drivers later onto
a non-existant bus, which will panic the kernel.
Fix that by checking that the bus was indeed initialized before trying to
register drivers on top of it.
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/usb/common/ulpi.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
index 0e6f968..0b0a5e7 100644
--- a/drivers/usb/common/ulpi.c
+++ b/drivers/usb/common/ulpi.c
@@ -132,6 +132,10 @@ int ulpi_register_driver(struct ulpi_driver *drv)
if (!drv->probe)
return -EINVAL;
+ /* Was the bus registered successfully? */
+ if (!ulpi_bus.p)
+ return -ENODEV;
+
Good catch. Otherwise it may trigger BUG() on driver_register().
I wonder if it would be nice to have a macro for that checking :)
Anyway,
Reviewed-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
Well, I was also encountering panic issue when running it on
Intel Bay Trail tablets. In my case, it's due to the execution
sequence. When ulpi bus is built-in, driver or device registered
before ulpi bus registration.
Thanks,
Baolu
drv->driver.bus = &ulpi_bus;
return driver_register(&drv->driver);
--
1.7.10.4
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