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Date:   Fri, 29 Jan 2021 15:20:32 -0600
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Marc MERLIN <marc_nouveau@merlins.org>
Cc:     nouveau@lists.freedesktop.org,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux PCI <linux-pci@vger.kernel.org>
Subject: Re: 5.9.11 still hanging 2mn at each boot and looping on nvidia-gpu
 0000:01:00.3: PME# enabled (Quadro RTX 4000 Mobile)
Message-ID: <20210129212032.GA99457@bjorn-Precision-5520>
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On Thu, Jan 28, 2021 at 04:56:26PM -0800, Marc MERLIN wrote:
> On Wed, Jan 27, 2021 at 03:33:00PM -0600, Bjorn Helgaas wrote:
> > Hi Marc, I appreciate your persistence on this.  I am frankly
> > surprised that you've put up with this so long.
>  
> Well, been using linux for 27 years, but also it's not like I have much
> of a choice outside of switching to windows, as tempting as it's getting
> sometimes ;)
> 
> > > after boot, when it gets the right trigger (not sure which ones), it
> > > loops on this evern 2 seconds, mostly forever.
> > > 
> > > I'm not sure if it's nouveau's fault or the kernel's PCI PME's fault, or something else.
> > 
> > IIUC there are basically two problems:
> > 
> >   1) A 2 minute delay during boot
> > Another random thought: is there any chance the boot delay could be
> > related to crypto waiting for entropy?
> 
> So, the 2mn hang went away after I added the nouveau firwmare in initrd.
> The only problem is that the nouveau driver does not give a very good
> clue as to what's going on and what to do.
>
> For comparison the intel iwlwifi driver is very clear about firmware
> it's trying to load, if it can't and what exact firmware you need to
> find on the internet (filename)

I guess you're referring to this in iwl_request_firmware()?

  IWL_ERR(drv, "check git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git\n"); 

How can we fix this in nouveau so we don't have the debug this again?
I don't really know how firmware loading works, but "git grep -A5
request_firmware drivers/gpu/drm/nouveau/" shows that we generally
print something when request_firmware() fails.

But I didn't notice those messages in your logs, so I'm probably
barking up the wrong tree.

> >   2) Some sort of event every 2 seconds that kills your battery life
> > Your machine doesn't sound unusual, and I haven't seen a flood of
> > similar reports, so maybe there's something unusual about your config.
> > But I really don't have any guesses for either one.
> 
> Honestly, there are not too many thinpad P73 running linux out there. I
> wouldn't be surprised if it's only a handful or two.
> 
> > It sounds like v5.5 worked fine and you first noticed the slow boot
> > problem in v5.8.  We *could* try to bisect it, but I know that's a lot
> > of work on your part.
> 
> I've done that in the past, to be honest now that it works after I added
> the firmware that nouveau started needing, and didn't need before, the
> hang at boot is gone for sure.
> The PCI PM wakeup issues on batteries happen sometimes still, but they
> are much more rare now.

So maybe the wakeups are related to having vs not having the nouveau
firmware?  I'm still curious about that, and it smells like a bug to
me, but probably something to do with nouveau where I have no hope of
debugging it.

> > Grasping for any ideas for the boot delay; could you boot with
> > "initcall_debug" and collect your "lsmod" output?  I notice async_tx
> > in some of your logs, but I have no idea what it is.  It's from
> > crypto, so possibly somewhat unusual?
> 
> Is this still neeeded? I think of nouveau does a better job of helping
> the user correct the issue if firmware is missing (I think intel even
> gives a URL in printk), that would probably be what's needed for the
> most part.

Nope, don't bother with this, thanks.

Bjorn