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From: Joerg Roedel <joro@8bytes.org>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/amd: Override wrong IVRS IOAPIC on Raven Ridge systems
Date: Wed, 14 Aug 2019 10:55:57 +0200	[thread overview]
Message-ID: <20190814085557.GB24321@8bytes.org> (raw)
In-Reply-To: <9CDD544D-DE4C-4AC6-B0DC-CD30C99EA71C@canonical.com>

On Tue, Aug 13, 2019 at 11:58:48AM +0800, Kai-Heng Feng wrote:
> at 23:39, Joerg Roedel <joro@8bytes.org> wrote:
> 
> > On Thu, Aug 08, 2019 at 06:17:07PM +0800, Kai-Heng Feng wrote:
> > > Raven Ridge systems may have malfunction touchpad or hang at boot if
> > > incorrect IVRS IOAPIC is provided by BIOS.
> > > 
> > > Users already found correct "ivrs_ioapic=" values, let's put them inside
> > > kernel to workaround buggy BIOS.
> > 
> > Will that still work when a fixed BIOS for these laptops is released?
> 
> Do you mean that we should stop applying these quirks once a BIOS fix is
> confirmed?

My concern is just that these quirks break some systems that don't need
them.

> We can modify the quirk to compare BIOS version, if there’s an unlikely BIOS
> update really fixes the issue.
> Before that happens, I think it’s OK to let the quirks stay this way.

A BIOS version check is not making things better here as it might lock
out systems that need the quirk. I think we can leave it as it for now,
but can you create a new file amd_iommu_quirks.c and move the code
there. And in the struct and function names please make clear that it is
about ivrs-quirks.


Regards,

	Joerg

  reply	other threads:[~2019-08-14  8:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08 10:17 [PATCH] iommu/amd: Override wrong IVRS IOAPIC on Raven Ridge systems Kai-Heng Feng
2019-08-09 15:39 ` Joerg Roedel
2019-08-13  3:58   ` Kai-Heng Feng
2019-08-14  8:55     ` Joerg Roedel [this message]
2019-08-17  6:35 ` [PATCH v2] " Kai-Heng Feng
2019-08-19  6:56   ` kbuild test robot

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