SoundWire: Perform clock stop in system suspend - #5875
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rfvirgil
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a lite review from Copilot
August 11, 2026 04:00
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Pull request overview
This PR updates the Intel SoundWire suspend flow to explicitly control whether in-band wake is enabled when stopping the bus, with the goal of reducing power by performing clock stop during system suspend and keeping the bus unwakeable in that state.
Changes:
- Extends the Intel SoundWire
stop_bushardware op and wrapper APIs to include awake_enableparameter. - Updates
intel_stop_bus()and suspend/runtime-suspend call sites to pass an explicit wake policy (wake disabled for system suspend; enabled for runtime clock-stop path).
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| include/linux/soundwire/sdw_intel.h | Extends the stop_bus hw op signature with wake_enable. |
| drivers/soundwire/intel.h | Updates inline wrapper and prototype for sdw_intel_stop_bus()/intel_stop_bus(). |
| drivers/soundwire/intel_bus_common.c | Updates intel_stop_bus() signature and removes implicit wake-enable derivation. |
| drivers/soundwire/intel_auxdevice.c | Updates suspend/runtime-suspend call sites to pass explicit wake_enable values. |
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Comment on lines
213
to
217
| if (clock_stop) { | ||
| ret = sdw_cdns_clock_stop(cdns, true); | ||
| if (ret < 0) | ||
| dev_err(dev, "%s: cannot stop clock: %d\n", __func__, ret); | ||
| else | ||
| wake_enable = true; | ||
| } |
sdw_get_clk_stop_mode() converts slave->dev.driver with drv_to_sdw_driver() and dereferences the result unconditionally. A Peripheral can be attached and enumerated on the bus while it has no driver bound to it, for example after its codec driver module has been removed, and in that case slave->dev.driver is NULL. sdw_bus_prep_clk_stop() walks every Peripheral which has a device number and is in ATTACHED or ALERT state, so the Manager's runtime suspend reaches such an unbound Peripheral and the container_of() arithmetic turns the NULL pointer into a small negative offset: BUG: unable to handle page fault for address: fffffffffffffff8 RIP: 0010:sdw_bus_prep_clk_stop+0x93/0x1d0 [soundwire_bus] Call Trace: sdw_cdns_clock_stop+0xbe/0x1d0 [soundwire_cadence] intel_stop_bus+0xc1/0x100 [soundwire_intel] intel_suspend_runtime+0x7b/0x160 [soundwire_intel] __rpm_callback+0x57/0x210 rpm_suspend+0xfc/0x660 pm_runtime_work+0xa4/0xb0 Take sdw_dev_lock and check slave->probed before looking at the driver, the same way sdw_slave_clk_stop_callback() and the other clock stop helpers do, and fall back to the mode advertised by the Peripheral property when no driver is bound. Fixes: 922ebc4 ("soundwire: bus: add CLOCK_STOP_MODE1 support back") Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Will add a wake_enable paramter to bus_clock ops first. This reverts commit cce6989.
Currently, we assume the bus is wakeable when the bus clock stops. But in some case like system suspend, we want to stop the bus but keep the bus unwakeable. No function change in this commit. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Perform clock stop with proper mode so that the Peripherals can enter the deserved power state. And keep the bus unwakeable because there is no need to wake up the bus in system suspend. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
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Pull request overview
Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.
Suppressed comments (3)
drivers/soundwire/bus.c:964
sdw_get_clk_stop_mode()readsslave->prop.clk_stop_mode1before takingslave->sdw_dev_lock, butpropis updated under that mutex during probe (drivers/soundwire/bus_type.c), so this can race withread_prop()when clock stop happens before probe completes. Consider taking the mutex first, reading the property under lock, and also guardingslave->dev.driverbefore callingdrv_to_sdw_driver().
enum sdw_clk_stop_mode mode;
mode = slave->prop.clk_stop_mode1 ? SDW_CLK_STOP_MODE1 : SDW_CLK_STOP_MODE0;
mutex_lock(&slave->sdw_dev_lock);
drivers/soundwire/intel_bus_common.c:209
enis a very generic name here; it’s used specifically as the post-clock-stop shim wake enable state. Either rename it (preferred) or at least annotate it to make the intent clearer.
bool en = false;
drivers/soundwire/intel_auxdevice.c:673
- This comment line is longer than typical kernel style and is hard to read in reviews/blame. Please wrap it onto multiple lines.
/* Perform clock stop with proper mode and keep the bus unwakeable in system suspend. */
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@plbossart Could you take a look? |
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To get lower power consumption when the Peripheral supports clock stop mode 1. And we keep the bus unwakeable because there is no need to wake up the bus in system suspend.