Re: [PATCH v2] usb: dwc3: core: Avoid resume dwc3 if already suspended in pm resume
From: wuliangfeng
Date: Fri Sep 15 2023 - 12:01:48 EST
Hi Thinh,
On 2023/9/12 8:08, Thinh Nguyen wrote:
Hi,
On Mon, Sep 11, 2023, William Wu wrote:
If we enable PM runtime auto suspend for dwc3 on rockchip
platforms (e.g. RK3562), it allows the dwc3 controller to
enter runtime suspend if usb cable detached and power off
the power domain of the controller. When system resume, if
the dwc3 already in runtime suspended, it Shouldn't access
the dwc3 registers in dwc3_resume() because its power domain
maybe power off.
Test on RK3562 tablet, this patch can help to avoid kernel
panic when accessing the dwc3 registers in dwc3_resume() if
the dwc3 is in runtime suspended and it's power domain is
power off.
The controller should be woken up before this step. Can you provide more
detail on what led to this?
Yes, the power domain of the usb controller will be enabled by the
framework of the pm generic domain before dwc3 resume if the system
enter suspend and exit suspend normally. However, in my test case，if the
system fail to enter suspend because of some devices's problem, and then
goto recovery process, the power domain of the usb controller will not
be enable before dwc3 resume.
e.g. some questions:
Who handles the waking up of the controller? Is it the phy driver? Is
the phy driver not detecting a resume? Or did the resume fail? Does this
occur consistently?
Thanks,
Thinh
This issue occurs occasionally on RK3562 EVB with Type-C USB, and enable
autosuspend for dwc3 controller.
Here is the test steps:
1. Power on the RK3562 EVB and the Type-C USB interface is in
unconnected state.
2. Makesure the dwc3 controller enter runtime suspend, and its power
domain is disabled.
3. Do system suspend/resume stress test.
4. The issue occurs occasionally with the following log:
[ 251.681091][ T4331] PM: suspend entry (deep)
[ 251.778975][ T4331] Filesystems sync: 0.097 seconds
[ 251.779025][ T4331] Freezing user space processes ... (elapsed 0.005
seconds) done.
[ 251.784819][ T4331] OOM killer disabled.
[ 251.784851][ T4331] Freezing remaining freezable tasks ... (elapsed
0.004 seconds) done.
[ 251.792719][ T503] [SKWIFI DBG] skw_suspend: WoW: enabled, skw
flags: 0x302
[ 251.803701][ T4331] PM: dpm_run_callback():
platform_pm_suspend.cfi_jt+0x0/0x8 returns -16
[ 251.803779][ T75] PM: PM: Pending Wakeup Sources: alarmtimer.0.auto
[ 251.803789][ T4331] PM: Device alarmtimer.0.a
[ 251.803928][ T4331] PM: Some devices failed to suspend, or early wake
event detected
[ 251.804141][ T75] [SKWIFI DBG] skw_resume: skw flags: 0x300
[ 251.804715][ C2] SError Interrupt on CPU2, code 0xbf000000 -- SError
[ 251.804725][ C2] CPU: 2 PID: 4331 Comm: binder:251_4 Tainted:
G WC E 5.10.157-android13-4-00006-g73f337804fbc-ab9881769 #1
[ 251.804732][ C2] Hardware name: Rockchip RK3562 RK817 TABLET LP4
Board (DT)
[ 251.804738][ C2] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO BTYPE=--)
[ 251.804743][ C2] pc : el1_abort+0x40/0x68
[ 251.804748][ C2] lr : el1_abort+0x28/0x68
......
[ 251.804965][ C2] Kernel panic - not syncing: Asynchronous SError
Interrupt
[ 251.804974][ C2] CPU: 2 PID: 4331 Comm: binder:251_4 Tainted:
G WC E 5.10.157-android13-4-00006-g73f337804fbc-ab9881769 #1
[ 251.804980][ C2] Hardware name: Rockchip RK3562 RK817 TABLET LP4
Board (DT)
[ 251.804984][ C2] Call trace:
[ 251.804990][ C2] dump_backtrace.cfi_jt+0x0/0x8
[ 251.804995][ C2] dump_stack_lvl+0xc0/0x13c
[ 251.805000][ C2] panic+0x174/0x468
[ 251.805006][ C2] arm64_serror_panic+0x1b0/0x200
[ 251.805010][ C2] do_serror+0x184/0x1e4
[ 251.805016][ C2] el1_error+0x94/0x118
[ 251.805020][ C2] el1_abort+0x40/0x68
[ 251.805026][ C2] el1_sync_handler+0x58/0x88
[ 251.805031][ C2] el1_sync+0x8c/0x140
[ 251.805035][ C2] dwc3_readl+0x30/0x1a0
[ 251.805040][ C2] dwc3_phy_setup+0x38/0x510
[ 251.805045][ C2] dwc3_core_init+0x68/0xcd4
[ 251.805051][ C2] dwc3_core_init_for_resume+0x10c/0x25c
[ 251.805056][ C2] dwc3_resume_common+0x44/0x3d0
[ 251.805061][ C2] dwc3_resume+0x5c/0xb8
[ 251.805067][ C2] dpm_run_callback+0x70/0x488
[ 251.805071][ C2] device_resume+0x250/0x2f8
[ 251.805077][ C2] dpm_resume+0x258/0x9dc
[ 251.805082][ C2] suspend_devices_and_enter+0x850/0xcac
In this case, during suspend process, because the device alarmtimer
failed to suspend, it break the system suspend in the funciton
suspend_devices_and_enter(), and goto platform_recover() directly
without enable the power domain of the controller, then trigger the
Kernel panic in dwc3_resume().
For a comparison, in the normal case, if the system enter suspend
normally, and after the system wakeup, the power domain of the
controller will be enable by the framework of the pm generic domain
before dwc3 resume.
The function call stack like this:
suspend_devices_and_enter -->
suspend_enter -->
dpm_resume_noirq --> dpm_noirq_resume_devices -->
device_resume_noirq --> genpd_resume_noirq --> rockchip_pd_power （enable
the power domain of the controller）
dpm_resume_end -->
dpm_resume --> device_resume --> dpm_run_callback -->
dwc3_resume (access the controller safely)
dpm_complete --> genpd_complete --> genpd_queue_power_off_work
suspend_finish --> suspend_thaw_processes --> genpd_power_off_work_fn
--> (diable the power domain of the controller to maintain the original
runtime suspend state)
Thanks,
William
Kernel panic - not syncing: Asynchronous SError Interrupt
Hardware name: Rockchip RK3562 RK817 TABLET LP4 Board (DT)
Call trace:
dump_backtrace.cfi_jt+0x0/0x8
dump_stack_lvl+0xc0/0x13c
panic+0x174/0x468
arm64_serror_panic+0x1b0/0x200
do_serror+0x184/0x1e4
el1_error+0x94/0x118
el1_abort+0x40/0x68
el1_sync_handler+0x58/0x88
el1_sync+0x8c/0x140
dwc3_readl+0x30/0x1a0
dwc3_phy_setup+0x38/0x510
dwc3_core_init+0x68/0xcd4
dwc3_core_init_for_resume+0x10c/0x25c
dwc3_resume_common+0x44/0x3d0
dwc3_resume+0x5c/0xb8
dpm_run_callback+0x70/0x488
device_resume+0x250/0x2f8
dpm_resume+0x258/0x9dc
Signed-off-by: William Wu <william.wu@xxxxxxxxxxxxxx>
---
Changes in v2:
- Remove Change-Id.
drivers/usb/dwc3/core.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 9c6bf054f15d..8274a44f2d6a 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2185,9 +2185,11 @@ static int dwc3_resume(struct device *dev)
pinctrl_pm_select_default_state(dev);
- ret = dwc3_resume_common(dwc, PMSG_RESUME);
- if (ret)
- return ret;
+ if (!pm_runtime_suspended(dwc->dev)) {
+ ret = dwc3_resume_common(dwc, PMSG_RESUME);
+ if (ret)
+ return ret;
+ }
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
--
2.17.1