On Do, 2015-11-26 at 13:30 -0700, Jason Gunthorpe wrote: > On Thu, Nov 26, 2015 at 08:01:34PM +0100, martin.wi...@ts.fujitsu.com wrote: > > From: Martin Wilck <martin.wi...@ts.fujitsu.com> > > > > Since b8b2c7d845d5, platform_drv_probe() is called for all platform > > devices. If drv->probe is NULL, and dev_pm_domain_attach() fails, > > platform_drv_probe() will return the error code from dev_pm_domain_attach(). > > > > This causes real_probe() to enter the "probe_failed" path and set > > dev->driver to NULL. Before b8b2c7d845d5, real_probe() would assume > > success if both dev->bus->probe and drv->probe are missing. > > > > This may cause a panic later. For example, inserting the tpm_tis > > driver with parameter "force=1" (i.e. registering tpm_tis as a platform > > driver) will panic in tpmm_chip_alloc() because dev->driver is NULL: > > > > chip->cdev.owner = chip->pdev->driver->owner; > > Is this happening because tpm_tis is not creating the platform device > properly? ie it just calls platform_device_register_simple and then > force initializes it via tpm_tis_init, which expects to be called from > a probe function with an attached driver. > > Instead we should setup a proper platform device with the default > IO range for x86 and let the driver core call tpm_tis_init via > tis_drv.probe. > > Would changing things in this way fix the problem you've observed?
I think so. Nonetheless, patch b8b2c7d845d5 introduced a change in the way platform device registration behaves. The platform device code seems to be prepared for cases where platform_driver->probe == NULL, so that case should be handled gracefully. Otherwise, failure should occur earlier, e.g. when platform_driver_register() is called with platform_driver->probe == NULL. tpm_tis may not be the only driver that uses platform_device_register_simple() in this way. > I have some patches to do this that are part of my OF enablement > series, but I can make something simpler that would deal with this > fairly quickly if you can test. Let's first wait what the platform guys say. Martin
