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authorSaravana Kannan <saravanak@google.com>2021-04-02 06:03:41 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-04-05 09:17:56 +0200
commitd46f3e3ed5276e756caf40f760d4902d15c12dcb (patch)
tree26e8d3ab879b9f511a248c47c11d2492ccf719ac /drivers/base/base.h
parentMerge 5.12-rc6 into driver-core-next (diff)
downloadlinux-d46f3e3ed5276e756caf40f760d4902d15c12dcb.tar.xz
linux-d46f3e3ed5276e756caf40f760d4902d15c12dcb.zip
driver core: Improve fw_devlink & deferred_probe_timeout interaction
deferred_probe_timeout kernel commandline parameter allows probing of consumer devices if the supplier devices don't have any drivers. fw_devlink=on will indefintely block probe() calls on a device if all its suppliers haven't probed successfully. This completely skips calls to driver_deferred_probe_check_state() since that's only called when a .probe() function calls framework APIs. So fw_devlink=on breaks deferred_probe_timeout. deferred_probe_timeout in its current state also ignores a lot of information that's now available to the kernel. It assumes all suppliers that haven't probed when the timer expires (or when initcalls are done on a static kernel) will never probe and fails any calls to acquire resources from these unprobed suppliers. However, this assumption by deferred_probe_timeout isn't true under many conditions. For example: - If the consumer happens to be before the supplier in the deferred probe list. - If the supplier itself is waiting on its supplier to probe. This patch fixes both these issues by relaxing device links between devices only if the supplier doesn't have any driver that could match with (NOT bound to) the supplier device. This way, we only fail attempts to acquire resources from suppliers that truly don't have any driver vs suppliers that just happen to not have probed yet. Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20210402040342.2944858-3-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/base.h')
-rw-r--r--drivers/base/base.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/base/base.h b/drivers/base/base.h
index 1b44ed588f66..e5f9b7e656c3 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -191,6 +191,7 @@ extern void device_links_driver_cleanup(struct device *dev);
extern void device_links_no_driver(struct device *dev);
extern bool device_links_busy(struct device *dev);
extern void device_links_unbind_consumers(struct device *dev);
+extern void fw_devlink_drivers_done(void);
/* device pm support */
void device_pm_move_to_tail(struct device *dev);