From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Cc: sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
mroos-Y27EyoLml9s@public.gmane.org,
sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org,
hch-jcswGhMUV9g@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: new SBus related DMA warnings in 4.18+git
Date: Tue, 28 Aug 2018 11:24:32 +0200 [thread overview]
Message-ID: <20180828092432.GB12488@lst.de> (raw)
In-Reply-To: <20180827.134136.955064444069965259.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
On Mon, Aug 27, 2018 at 01:41:36PM -0700, David Miller wrote:
> From: Sam Ravnborg <sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org>
> Date: Mon, 27 Aug 2018 21:15:18 +0200
>
> > Why not fix the drivers rather than papering over the fact
> > that they are missing the DMA mask?
> >
> > We are in the lucky situation the Meelis can test any patches.
>
> SBUS drivers never set the mask because they never needed to and could
> use the default, since SBUS IOMMUs were quite universal in nature.
In addition to that the historical expectation is that you can do
dma to platform_devices without setup, and for some reason sbus
devices all show up as platform_devices.
> I think it's more error prone to add the mask setting to every single
> SBUS driver than to just have the core setup the default properly.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Cc: sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
mroos-Y27EyoLml9s@public.gmane.org,
sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org,
hch-jcswGhMUV9g@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: new SBus related DMA warnings in 4.18+git
Date: Tue, 28 Aug 2018 09:24:32 +0000 [thread overview]
Message-ID: <20180828092432.GB12488@lst.de> (raw)
In-Reply-To: <20180827.134136.955064444069965259.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
On Mon, Aug 27, 2018 at 01:41:36PM -0700, David Miller wrote:
> From: Sam Ravnborg <sam@ravnborg.org>
> Date: Mon, 27 Aug 2018 21:15:18 +0200
>
> > Why not fix the drivers rather than papering over the fact
> > that they are missing the DMA mask?
> >
> > We are in the lucky situation the Meelis can test any patches.
>
> SBUS drivers never set the mask because they never needed to and could
> use the default, since SBUS IOMMUs were quite universal in nature.
In addition to that the historical expectation is that you can do
dma to platform_devices without setup, and for some reason sbus
devices all show up as platform_devices.
> I think it's more error prone to add the mask setting to every single
> SBUS driver than to just have the core setup the default properly.
next prev parent reply other threads:[~2018-08-28 9:24 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-26 7:48 new SBus related DMA warnings in 4.18+git Meelis Roos
2018-08-26 7:48 ` Meelis Roos
[not found] ` <alpine.LRH.2.21.1808260902280.22219-ptEonEWSGqKptlylMvRsHA@public.gmane.org>
2018-08-27 15:47 ` Christoph Hellwig
2018-08-27 15:47 ` Christoph Hellwig
[not found] ` <20180827154716.GA30492-jcswGhMUV9g@public.gmane.org>
2018-08-27 19:04 ` Meelis Roos
2018-08-27 19:04 ` Meelis Roos
[not found] ` <alpine.LRH.2.21.1808272203270.28446-ptEonEWSGqKptlylMvRsHA@public.gmane.org>
2018-08-28 9:29 ` Christoph Hellwig
2018-08-28 9:29 ` Christoph Hellwig
[not found] ` <20180828092915.GC12488-jcswGhMUV9g@public.gmane.org>
2018-08-28 10:30 ` Meelis Roos
2018-08-28 10:30 ` Meelis Roos
[not found] ` <alpine.LRH.2.21.1808281330270.13945-ptEonEWSGqKptlylMvRsHA@public.gmane.org>
2018-08-28 11:43 ` Christoph Hellwig
2018-08-28 11:43 ` Christoph Hellwig
[not found] ` <20180828114358.GA14519-jcswGhMUV9g@public.gmane.org>
2018-08-29 5:47 ` Meelis Roos
2018-08-29 5:47 ` Meelis Roos
[not found] ` <alpine.LRH.2.21.1808281649580.19903-ptEonEWSGqKptlylMvRsHA@public.gmane.org>
2018-08-29 5:51 ` Christoph Hellwig
2018-08-29 5:51 ` Christoph Hellwig
2018-08-27 19:15 ` Sam Ravnborg
2018-08-27 19:15 ` Sam Ravnborg
[not found] ` <20180827191518.GA26665-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org>
2018-08-27 20:41 ` David Miller
2018-08-27 20:41 ` David Miller
[not found] ` <20180827.134136.955064444069965259.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2018-08-28 9:24 ` Christoph Hellwig [this message]
2018-08-28 9:24 ` Christoph Hellwig
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