Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 19 Apr 2017 21:52:17 -0700 | Subject | Re: [PATCH 0/5] nvme APST fixes/improvements for 4.11 |
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On Wed, Apr 19, 2017 at 8:55 PM, Andy Lutomirski <luto@kernel.org> wrote: > On Wed, Apr 19, 2017 at 8:10 PM, Jens Axboe <axboe@kernel.dk> wrote: >> On Wed, Apr 19 2017, Andy Lutomirski wrote: >>> Sorry for waiting so long for this. I was waiting for feedback from >>> Samsung, but they haven't root-caused the issue yet, and I should >>> have just done this from the beginning. >>> >>> This series makes APST more debuggable and updates the quirk list. >>> The quirks I'm aware of are: >>> >>> - Samsung 950 series SSDs in Dell XPS 15 9550 and Precision 5510 >>> laptops (which are essentially the same laptop) can lose their >>> PCIe link if they're allowed to use the deepest APST state. >>> Samsung engineers have an affected system and are working on >>> it. The same exact SSDs in other machines (even an XPS 13) >>> seem to work fine. >>> >>> - One Toshiba device malfunctions if APST is used at all. >> >> You need to split this series in two, patches 1-3 can wait. For 4.11, >> all we need to do is turn off APST on any device that potentially has >> this problem. >> >>> One thing that improves my confidence that there aren't too many >>> more problems with APST is that Ubuntu has backported APST to Zesty, >>> so it's already gotten a bit of testing in a widely used (if very >>> new) release. >> >> Honestly, I think the best path for 4.11 is to turn off APST by default, >> make it opt-in instead. I don't share your optimism here, as I made >> clear back from before we even merged this feature. >> >> > > I can make it so that force_apst=0 means no APST and force_apst=1 mean > yes APST and we could try again with a quirk list for 4.12. There's a > decent chance that a few more weeks with Ubuntu having APST on will > shake out all the problems fairly quickly.
Here's a more concrete and more sensible proposal:
For 4.11:
force_apst=0: Default. APST off on all Samsung 950-like devices regardless of what laptop and on the Toshiba device. force_apst=1: Use APST except where known bad. APST deepest state disabled on Samsung 950-like devices on XPS 15 and Precision 5510. APST off on the Toshiba device. force_apst=2: APST fully on regardless of any quirks.
For 4.12-rc1: force_apst=0 works like force_apst=1, but we keep both values for compatibility and in case we need to add another overly broad quirk some day.
Would something like this make sense?
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