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| author | Martin Wilck <Martin.Wilck@ts.fujitsu.com> | 2015-11-30 11:50:05 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-26 16:47:25 (GMT) |
| commit | 25cad69f21f5532d99e2ee73c8ab6512bcab614c (patch) | |
| tree | 0bfc4b5140547e81b9d126b7e1573d4d619d662c | |
| parent | 92e963f50fc74041b5e9e744c330dca48e04f08d (diff) | |
| download | linux-25cad69f21f5532d99e2ee73c8ab6512bcab614c.tar.xz | |
base/platform: Fix platform drivers with no probe callback
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 were missing. As a result,
a device and driver could be "bound" together just by matching their names;
this doesn't work any more after b8b2c7d845d5.
This may cause problems later for certain usage of platform_driver_register()
and platform_device_register_simple(). I observed a panic while loading
the tpm_tis driver with parameter "force=1" (i.e. registering tpm_tis as
a platform driver), because tpm_tis_init's assumption that the device
returned by platform_device_register_simple() was bound didn't hold any more
(tpmm_chip_alloc() dereferences chip->pdev->driver, causing panic).
This patch restores the previous (4.3.0 and earlier) behavior of
platform_drv_probe() in the case when the associated platform driver has
no "probe" function.
Fixes: b8b2c7d845d5 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally")
Signed-off-by: Martin Wilck <Martin.Wilck@ts.fujitsu.com>
Cc: stable <stable@vger.kernel.org> # 4.4
Cc: Martin Fuzzey <mfuzzey@parkeon.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/base/platform.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 73d6e5d..f437afa 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -558,10 +558,15 @@ static int platform_drv_probe(struct device *_dev) return ret; ret = dev_pm_domain_attach(_dev, true); - if (ret != -EPROBE_DEFER && drv->probe) { - ret = drv->probe(dev); - if (ret) - dev_pm_domain_detach(_dev, true); + if (ret != -EPROBE_DEFER) { + if (drv->probe) { + ret = drv->probe(dev); + if (ret) + dev_pm_domain_detach(_dev, true); + } else { + /* don't fail if just dev_pm_domain_attach failed */ + ret = 0; + } } if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { |