diff options
| author | Pin-yen Lin <treapking@chromium.org> | 2025-09-26 18:23:18 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2025-09-27 14:10:51 +0200 |
| commit | 632d31067be2f414c57955efcf29c79290cc749b (patch) | |
| tree | 95ad109562e2ce75e957d7854892aaf51e1b29a0 | |
| parent | 3ce3f569991347d2085925041f4932232da43bcf (diff) | |
PM: sleep: Do not wait on SYNC_STATE_ONLY device links
Device links with DL_FLAG_SYNC_STATE_ONLY should not affect system
suspend and resume, and functions like device_reorder_to_tail() and
device_link_add() don't try to reorder the consumers with that flag.
However, dpm_wait_for_consumers() and dpm_wait_for_suppliers() don't
check thas flag before triggering dpm_wait(), leading to potential hang
during suspend/resume.
This can be reproduced on MT8186 Corsola Chromebook with devicetree like:
usb-a-connector {
compatible = "usb-a-connector";
port {
usb_a_con: endpoint {
remote-endpoint = <&usb_hs>;
};
};
};
usb_host {
compatible = "mediatek,mt8186-xhci", "mediatek,mtk-xhci";
port {
usb_hs: endpoint {
remote-endpoint = <&usb_a_con>;
};
};
};
In this case, the two nodes form a cycle and a SYNC_STATE_ONLY devlink
between usb_host (supplier) and usb-a-connector (consumer) is created.
Address this by exporting device_link_flag_is_sync_state_only() and
making dpm_wait_for_consumers() and dpm_wait_for_suppliers() use it
when deciding if dpm_wait() should be called.
Fixes: 05ef983e0d65a ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Link: https://patch.msgid.link/20250926102320.4053167-1-treapking@chromium.org
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | drivers/base/base.h | 1 | ||||
| -rw-r--r-- | drivers/base/core.c | 2 | ||||
| -rw-r--r-- | drivers/base/power/main.c | 6 |
3 files changed, 6 insertions, 3 deletions
diff --git a/drivers/base/base.h b/drivers/base/base.h index 700aecd22fd3..86fa7fbb3548 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -248,6 +248,7 @@ void device_links_driver_cleanup(struct device *dev); void device_links_no_driver(struct device *dev); bool device_links_busy(struct device *dev); void device_links_unbind_consumers(struct device *dev); +bool device_link_flag_is_sync_state_only(u32 flags); void fw_devlink_drivers_done(void); void fw_devlink_probing_done(void); diff --git a/drivers/base/core.c b/drivers/base/core.c index d22d6b23e758..a54ec6df1058 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -287,7 +287,7 @@ static bool device_is_ancestor(struct device *dev, struct device *target) #define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \ DL_FLAG_CYCLE | \ DL_FLAG_MANAGED) -static inline bool device_link_flag_is_sync_state_only(u32 flags) +bool device_link_flag_is_sync_state_only(u32 flags) { return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY; } diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index e3a7f25bf8d3..c97f8b139dc2 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -278,7 +278,8 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async) * walking. */ dev_for_each_link_to_supplier(link, dev) - if (READ_ONCE(link->status) != DL_STATE_DORMANT) + if (READ_ONCE(link->status) != DL_STATE_DORMANT && + !device_link_flag_is_sync_state_only(link->flags)) dpm_wait(link->supplier, async); device_links_read_unlock(idx); @@ -335,7 +336,8 @@ static void dpm_wait_for_consumers(struct device *dev, bool async) * unregistration). */ dev_for_each_link_to_consumer(link, dev) - if (READ_ONCE(link->status) != DL_STATE_DORMANT) + if (READ_ONCE(link->status) != DL_STATE_DORMANT && + !device_link_flag_is_sync_state_only(link->flags)) dpm_wait(link->consumer, async); device_links_read_unlock(idx); |