On Fri, Sep 15, 2023, wuliangfeng wrote: > 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. Ok. > > > 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(). > Thanks for the details. > > 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) > At what step do we restore the power domain when this happen? Looks like there's a missing step in the suspend failure recovery to recover the power domain. What we're doing here seems more like a workaround to that, which unfortunately makes the code logic looks unclear IMO. Can this be fixed in the lower layer? Thanks, Thinh
