Bjorn, On 4/12/2017 3:19 PM, Rajat Jain wrote: > On Fri, Apr 7, 2017 at 9:55 PM, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote: >> Now that we added a hook to be called from device_add, save the >> default values from the HW registers early in the boot for further >> reuse during hot device add/remove operations. >> >> If the link is down during boot, assume that we want to enable L0s >> and L1 following hotplug insertion as well as L1SS if supported. > > IIUC, so far POLICY_DEFAULT meant that we'd just use & follow what > BIOS has done, and play it safe (never try to be more opportunistic). > With this change however, we'd be slightly overstepping and giving > ourselves benefit of doubt if the BIOS could not enable ASPM states > because the link was not up. This may be good, but I think we should > call it out, and add some more elaborate comment on the POLICY_DEFAULT > description (what to, and what not to expect in different situations). > > It is important because existing systems today, that used to boot > without cards and later hotplugged them, didn't have ASPM states > enabled. They will now suddenly start seeing all ASPM states enabled > including L1 substates for the first time (if supported). > Rajat has a good point here. Would you like me to update the ASPM document with this new behavior for hotplug? Do you have another behavior preference when it comes this? Sinan -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
