user/sven/linux.git/drivers/devfreq/devfreq.c, branch v5.5

PM / devfreq: Use PM QoS for sysfs min/max_freq

2019-12-09T03:19:16Z

Switch the handling of min_freq and max_freq from sysfs to use the dev_pm_qos_request interface. Since PM QoS handles frequencies as kHz this change reduces the precision of min_freq and max_freq. This shouldn't introduce problems because frequencies which are not an integer number of kHz are likely not an integer number of Hz either. Try to ensure compatibility by rounding min values down and rounding max values up. Signed-off-by: Leonard Crestez Acked-by: Chanwoo Choi Reviewed-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke [cw00.choi: Return -EAGAIN instead of -EINVAL if dev_pm_qos is inactive] Signed-off-by: Chanwoo Choi

PM / devfreq: Add PM QoS support

2019-12-09T03:19:16Z

Register notifiers with the PM QoS framework in order to respond to requests for DEV_PM_QOS_MIN_FREQUENCY and DEV_PM_QOS_MAX_FREQUENCY. No notifiers are added by this patch but PM QoS constraints can be imposed externally (for example from other devices). Signed-off-by: Leonard Crestez Acked-by: Chanwoo Choi Reviewed-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke Signed-off-by: Chanwoo Choi

PM / devfreq: Don't fail devfreq_dev_release if not in list

2019-12-09T03:19:16Z

Right now devfreq_dev_release will print a warning and abort the rest of the cleanup if the devfreq instance is not part of the global devfreq_list. But this is a valid scenario, for example it can happen if the governor can't be found or on any other init error that happens after device_register. Initialize devfreq->node to an empty list head in devfreq_add_device so that list_del becomes a safe noop inside devfreq_dev_release and we can continue the rest of the cleanup. Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Introduce get_freq_range helper

2019-12-09T03:19:16Z

Moving handling of min/max freq to a single function and call it from update_devfreq and for printing min/max freq values in sysfs. This changes the behavior of out-of-range min_freq/max_freq: clamping is now done at evaluation time. This means that if an out-of-range constraint is imposed by sysfs and it later becomes valid then it will be enforced. Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Set scaling_max_freq to max on OPP notifier error

2019-12-09T03:19:15Z

The devfreq_notifier_call functions will update scaling_min_freq and scaling_max_freq when the OPP table is updated. If fetching the maximum frequency fails then scaling_max_freq remains set to zero which is confusing. Set to ULONG_MAX instead so we don't need special handling for this case in other places. Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Fix devfreq_notifier_call returning errno

2019-12-09T03:19:15Z

Notifier callbacks shouldn't return negative errno but one of the NOTIFY_OK/DONE/BAD values. The OPP core will ignore return values from notifiers but returning a value that matches NOTIFY_STOP_MASK will stop the notification chain. Fix by always returning NOTIFY_OK. Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Add missing locking while setting suspend_freq

2019-11-29T11:50:34Z

Commit 2abb0d5268ae ("PM / devfreq: Lock devfreq in trans_stat_show") revealed a missing locking while calling devfreq_update_status() function during suspend/resume cycle. Code analysis revealed that devfreq_set_target() function was called without needed locks held for setting device specific suspend_freq if such has been defined. This patch fixes that by adding the needed locking, what fixes following kernel warning on Exynos4412-based OdroidU3 board during system suspend: PM: suspend entry (deep) Filesystems sync: 0.002 seconds Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled. Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1385 at drivers/devfreq/devfreq.c:204 devfreq_update_status+0xc0/0x188 Modules linked in: CPU: 2 PID: 1385 Comm: rtcwake Not tainted 5.4.0-rc6-next-20191111 #6848 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xb4/0xe0) [] (dump_stack) from [] (__warn+0xf4/0x10c) [] (__warn) from [] (warn_slowpath_fmt+0xb0/0xb8) [] (warn_slowpath_fmt) from [] (devfreq_update_status+0xc0/0x188) [] (devfreq_update_status) from [] (devfreq_set_target+0xb0/0x15c) [] (devfreq_set_target) from [] (devfreq_suspend+0x2c/0x64) [] (devfreq_suspend) from [] (dpm_suspend+0xa4/0x57c) [] (dpm_suspend) from [] (dpm_suspend_start+0x98/0xa0) [] (dpm_suspend_start) from [] (suspend_devices_and_enter+0xec/0xc74) [] (suspend_devices_and_enter) from [] (pm_suspend+0x340/0x410) [] (pm_suspend) from [] (state_store+0x6c/0xc8) [] (state_store) from [] (kernfs_fop_write+0x10c/0x228) [] (kernfs_fop_write) from [] (__vfs_write+0x30/0x1d0) [] (__vfs_write) from [] (vfs_write+0xa4/0x180) [] (vfs_write) from [] (ksys_write+0x60/0xd8) [] (ksys_write) from [] (ret_fast_syscall+0x0/0x28) Exception stack(0xed3d7fa8 to 0xed3d7ff0) ... irq event stamp: 9667 hardirqs last enabled at (9679): [] _raw_spin_unlock_irq+0x20/0x58 hardirqs last disabled at (9698): [] __schedule+0xd8/0x818 softirqs last enabled at (9694): [] __do_softirq+0x4fc/0x5fc softirqs last disabled at (9719): [] irq_exit+0x16c/0x170 ---[ end trace 41ac5b57d046bdbc ]--- ------------[ cut here ]------------ Signed-off-by: Marek Szyprowski Acked-by: Chanwoo Choi Signed-off-by: Rafael J. Wysocki

PM / devfreq: Add new interrupt_driven flag for governors

2019-11-06T03:04:01Z

Currently interrupt-driven governors (like NVIDIA Tegra30 ACTMON governor) are used to set polling_ms=0 in order to avoid periodic polling of device status by devfreq core. This means that polling interval can't be changed by userspace for such governors. The new governor flag allows interrupt-driven governors to convey that devfreq core shouldn't perform polling of device status and thus generic devfreq polling interval could be supported by these governors now. Signed-off-by: Dmitry Osipenko Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Lock devfreq in trans_stat_show

2019-11-06T03:04:00Z

There is no locking in this sysfs show function so stats printing can race with a devfreq_update_status called as part of freq switching or with initialization. Also add an assert in devfreq_update_status to make it clear that lock must be held by caller. Fixes: 39688ce6facd ("PM / devfreq: account suspend/resume for stats") Cc: stable@vger.kernel.org Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi

PM / devfreq: Check NULL governor in available_governors_show

2019-11-06T03:03:59Z

The governor is initialized after sysfs attributes become visible so in theory the governor field can be NULL here. Fixes: bcf23c79c4e46 ("PM / devfreq: Fix available_governor sysfs") Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi