Re: [PATCH v4] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung 860 and 870 SSD.

From: torvic9@mailbox.org
To: Hans de Goede <hdegoede@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"hpa@redhat.com" <hpa@redhat.com>
Cc: "linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"damien.lemoal@wdc.com" <damien.lemoal@wdc.com>
Subject: Re: [PATCH v4] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung 860 and 870 SSD.
Date: Wed, 1 Sep 2021 13:11:01 +0200 (CEST)	[thread overview]
Message-ID: <1693972970.60125.1630494661286@office.mailbox.org> (raw)
In-Reply-To: <2df1c3d5-301d-dc46-7f9f-d28be2933bd3@redhat.com>

> Hans de Goede <hdegoede@redhat.com> hat am 01.09.2021 11:38 geschrieben:
> 
>  
> Hi,
> 
> On 9/1/21 10:55 AM, Hans de Goede wrote:
> > Hi Tor,
> > 
> > On 9/1/21 9:37 AM, torvic9@mailbox.org wrote:
> >> (Sorry for not doing a proper reply)
> >>
> >> Hello,
> >> Noob here.
> >> I have a Samsung 860 Pro connected to a AMD X570 chipset mainboard and
> >> it just works flawlessly on 5.13 and 5.14.
> >> Are you sure that *every* 860/870 is concerned by this problem on
> >> *every* AMD controller?
> > 
> > I am pretty sure that every 860 / 870 EVO is affected,
> > I am not sure if the PRO is also affected.
> 
> So while reading https://bugzilla.kernel.org/show_bug.cgi?id=201693
> again to add a comment asking if anyone was seeing this on a
> pro to I found existing comments of both queued-trims being
> an issue on the 860 pro, as well as the 860 pro having issues
> with some AMD sata controllers.
> 
> So it seems safe to say that the 860 pro has the same issues
> as the 860 and 870 evo models. Chances are you don't have
> discard support enabled causing you to not see the queued-trim
> issues (which means you also won't see any difference from
> disabling support for queued-trim commands).

Thanks for your answer, Hans.

If you mean the "discard" mount option, then yes, you're correct,
I don't use this because some (apparently) knowledgeable people
recommended against using it especially on LUKS partitions.
I don't know whether that's true though, it might be outdated.
I do however do manual TRIMs with "fstrim".

> 
> So this just leaves your question of:
> 
> "concerned by this problem on *every* AMD controller?"
> 
> Where "this problem" is needing to completely disable NCQ
> and I guess the answer is no, not every AMD controller
> is affected. Still the plan is to err on the safe side for now,
> allowing overriding this from the kernel cmdline with:
> 
> libata.force=ncqamd

I agree to do it in a safe way, that sounds like a good solution.

> 
> I will add a comment to:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=201693
> 
> Asking for PCI-ids of the controllers where people are seeing
> this and then maybe we can narrow down the "AMD" check in a
> future follow up patch.

I can send you PCI and device IDs later if it helps.

> 
> Regards,
> 
> Hans