From: 'Christoph Hellwig' <hch@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: David Wang <davidwang@zhaoxin.com>,
'Christoph Hellwig' <hch@infradead.org>,
mingo@redhat.com, hpa@zytor.com, gregkh@linuxfoundation.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
brucechang@via-alliance.com, cooperyan@zhaoxin.com,
qiyuanwang@zhaoxin.com, benjaminpan@viatech.com,
lukelin@viacpu.com, timguo@zhaoxin.com
Subject: Re: [PATCH] x86/dma-mapping: override via_no_dac for new VIA PCI bridges
Date: Tue, 17 Apr 2018 06:00:40 -0700 [thread overview]
Message-ID: <20180417130040.GA9426@infradead.org> (raw)
In-Reply-To: <alpine.DEB.2.21.1804171052440.1694@nanos.tec.linutronix.de>
On Tue, Apr 17, 2018 at 10:54:37AM +0200, Thomas Gleixner wrote:
> The question was rather to have a list of PCI IDs for those chipsets which
> have the problem and set the 'disable' flag only for those. That makes a lot
> more sense than making a list of new chips which disable the disable flag.
Agreed.
There are a few other things I'd like to do in this area while we're
at it (I'm happy to do the work, not trying to offload it to David
or Thomas):
(1) make the nodac flag a per-device flag. Set for every device
under one of the affected VIA bridges, or for all PCI devices
if the nodac command line option is used
(2) move that flag into the common struct device (or the to be
designed dma struct hanging off it in the future) and make that
bit handled in common code as there is a common Xilinx host
bridge with a 32-bit dma limitation
(3) kill of the forcesac option, which was a strange performance
tweak back in plain PCI days, which probably didn't even work
as expected to start with.
next prev parent reply other threads:[~2018-04-17 13:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-17 8:44 [PATCH] x86/dma-mapping: override via_no_dac for new VIA PCI bridges David Wang
2018-04-17 8:54 ` Thomas Gleixner
2018-04-17 13:00 ` 'Christoph Hellwig' [this message]
2018-04-17 13:33 ` Thomas Gleixner
-- strict thread matches above, loose matches on Subject: below --
2018-04-16 9:26 David Wang
2018-04-16 12:33 ` Christoph Hellwig
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