Messages in this thread | | | Date | Thu, 21 May 2015 14:39:48 +0800 | From | "Lu, Baolu" <> | Subject | Re: [PATCH] usb: ulpi: don't register drivers if bus doesn't exist |
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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@oracle.com> >> --- >> 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@linux.intel.com>
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 >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >
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