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platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers

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dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
finishing probe successfully to probe themselves.

Currently if dell-wmi-descriptor fails probing in a non-recoverable way
(such as invalid header) dell-wmi and dell-smbios-wmi will continue to
try to redo probing due to deferred probing.

To solve this have the dependent drivers query the dell-wmi-descriptor
driver whether the descriptor has been determined valid. The possible
results are:
-ENODEV: Descriptor GUID missing from WMI bus
-EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
 and use deferred probing
< 0: Descriptor probed, invalid.  Dependent driver should return an
 error.
0: Successful descriptor probe, dependent driver can continue

Successful descriptor probe still doesn't mean that the descriptor driver
is necessarily bound at the time of initialization of dependent driver.
Userspace can unbind the driver, so all methods used from driver
should still be verified to return success values otherwise deferred
probing be used.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
This commit is contained in:
Mario Limonciello
2017-11-09 11:49:10 -06:00
committed by Darren Hart (VMware)
parent 8b9528a6d9
commit 868b8d33f9
4 changed files with 30 additions and 5 deletions
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5
drivers/platform/x86/dell-smbios-wmi.c
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@@ -151,8 +151,9 @@ static int dell_smbios_wmi_probe(struct wmi_device *wdev)
int count;
int ret;
if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
return -ENODEV;
ret = dell_wmi_get_descriptor_valid();
if (ret)
return ret;
priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
GFP_KERNEL);