diff options
| author | Saravana Kannan <saravanak@google.com> | 2020-07-01 12:42:57 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-10 15:20:38 +0200 |
| commit | cec72f3efc6272420c2c2c699607f03d09b93e41 (patch) | |
| tree | e8645d83c161bcc856de5ecd6d231c4a9787e00d /drivers/base/dd.c | |
| parent | 9ebcfadb0610322ac537dd7aa5d9cbc2b2894c68 (diff) | |
| download | linux-cec72f3efc6272420c2c2c699607f03d09b93e41.tar.bz2 | |
driver core: Don't do deferred probe in parallel with kernel_init thread
The current deferred probe implementation can mess up suspend/resume
ordering if deferred probe thread is kicked off in parallel with the
main initcall thread (kernel_init thread) [1].
For example:
Say device-B is a consumer of device-A.
Initcall thread Deferred probe thread
=============== =====================
1. device-A is added.
2. device-B is added.
3. dpm_list is now [device-A, device-B].
4. driver-A defers probe of device-A.
5. device-A is moved to
end of dpm_list
6. dpm_list is now
[device-B, device-A]
7. driver-B is registereed and probes device-B.
8. dpm_list stays as [device-B, device-A].
The reverse order of dpm_list is used for suspend. So in this case
device-A would incorrectly get suspended before device-B.
Commit 716a7a259690 ("driver core: fw_devlink: Add support for batching
fwnode parsing") kicked off the deferred probe thread early during boot
to run in parallel with the initcall thread and caused suspend/resume
regressions. This patch removes the parallel run of the deferred probe
thread to avoid the suspend/resume regressions.
[1] - https://lore.kernel.org/lkml/CAGETcx8W96KAw-d_siTX4qHB_-7ddk0miYRDQeHE6E0_8qx-6Q@mail.gmail.com/
Fixes: 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/dd.c')
| -rw-r--r-- | drivers/base/dd.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9a1d940342ac..48ca81cb8ebc 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -164,11 +164,6 @@ static void driver_deferred_probe_trigger(void) if (!driver_deferred_probe_enable) return; - driver_deferred_probe_force_trigger(); -} - -void driver_deferred_probe_force_trigger(void) -{ /* * A successful probe means that all the devices in the pending list * should be triggered to be reprobed. Move all the deferred devices |