Hi Felipe, On 1/11/2018 1:44 PM, Felipe Balbi wrote: > Hi, > > Manu Gautam <mgautam@xxxxxxxxxxxxxx> writes: >>> On 27/09/17 14:19, Manu Gautam wrote: >>>> Driver powers-off PHYs and reinitializes DWC3 core and gadget on >>>> resume. While this works fine for gadget mode but in host >>>> mode there is not re-initialization of host stack. Also, resetting >>>> bus as part of bus_suspend/resume is not correct which could affect >>>> (or disconnect) connected devices. >>>> Fix this by not reinitializing core on suspend/resume in host mode >>>> for HOST only and OTG/drd configurations. >>>> >>> All this seems correct but we (TI) were relying on dwc3_core_exit() to be called >>> during dwc3_suspend() to have the lowest power state for our platforms. >>> >>> After this patch, DWC3 controller and PHYs won't be turned off thus >>> preventing our platform from reaching low power levels. >>> >>> So this is a regression for us (TI) in v4.15-rc. >>> >>> Felipe, do you agree? >>> >>> If yes I can send a patch which fixes the regression >>> and also makes USB host work after suspend/resume. >>> >> I think it will be better to separate runtime_suspend and pm_suspend handling for >> host mode in dwc3. Powering offf/on PHYs and dwc3_core_exit/init across system >> suspend-resume should be ok but doing that for runtime suspend-resume is not >> correct. > it sure is. It's part of hibernation-while-disconnected programming sequence > >> Let me know if that sounds ok, I can provide a patch for same instead of >> reverting this which affects runtime PM with dwc3 host. > nope, that would break platforms using hibernation Please don't mind me asking this if it is very basic, I am probably missing something there We should be able to distinguish between runtime_pm vs system_suspend/hibernation and then process accordingly. In host mode runtime suspend/resume could happen very often with device connected, and resetting h/w on every runtime_resume might not be desired. And PHYs drivers can also support runtime_suspend which would be preferred instead of shutting down phy. -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
