From: Christoph Hellwig <hch@lst.de>
To: Oliver Neukum <oneukum@suse.com>
Cc: Christoph Hellwig <hch@lst.de>,
Alan Stern <stern@rowland.harvard.edu>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: Re: How to resolve an issue in swiotlb environment?
Date: Wed, 12 Jun 2019 14:06:53 +0200 [thread overview]
Message-ID: <20190612120653.GA25285@lst.de> (raw)
In-Reply-To: <1560339966.9728.18.camel@suse.com>
On Wed, Jun 12, 2019 at 01:46:06PM +0200, Oliver Neukum wrote:
> > Thay is someething the virt_boundary prevents. But could still give
> > you something like:
> >
> > 1536 4096 4096 1024
> >
> > or
> > 1536 16384 8192 4096 16384 512
>
> That would kill the driver, if maxpacket were 1024.
>
> USB has really two kinds of requirements
>
> 1. What comes from the protocol
> 2. What comes from the HCD
>
> The protocol wants just multiples of maxpacket. XHCI can satisfy
> that in arbitrary scatter/gather. Other HCs cannot.
We have no real way to enforce that for the other HCs unfortunately.
I can't really think of any better way to handle their limitations
except for setting max_segments to 1 or bounce buffering.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Oliver Neukum <oneukum@suse.com>
Cc: Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Christoph Hellwig <hch@lst.de>
Subject: Re: How to resolve an issue in swiotlb environment?
Date: Wed, 12 Jun 2019 14:06:53 +0200 [thread overview]
Message-ID: <20190612120653.GA25285@lst.de> (raw)
In-Reply-To: <1560339966.9728.18.camel@suse.com>
On Wed, Jun 12, 2019 at 01:46:06PM +0200, Oliver Neukum wrote:
> > Thay is someething the virt_boundary prevents. But could still give
> > you something like:
> >
> > 1536 4096 4096 1024
> >
> > or
> > 1536 16384 8192 4096 16384 512
>
> That would kill the driver, if maxpacket were 1024.
>
> USB has really two kinds of requirements
>
> 1. What comes from the protocol
> 2. What comes from the HCD
>
> The protocol wants just multiples of maxpacket. XHCI can satisfy
> that in arbitrary scatter/gather. Other HCs cannot.
We have no real way to enforce that for the other HCs unfortunately.
I can't really think of any better way to handle their limitations
except for setting max_segments to 1 or bounce buffering.
_______________________________________________
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iommu@lists.linux-foundation.org
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next prev parent reply other threads:[~2019-06-12 12:07 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-03 6:42 How to resolve an issue in swiotlb environment? Yoshihiro Shimoda
2019-06-03 6:42 ` Yoshihiro Shimoda
2019-06-07 12:00 ` Yoshihiro Shimoda
2019-06-07 12:00 ` Yoshihiro Shimoda
2019-06-10 7:31 ` Biju Das
2019-06-10 7:31 ` Biju Das
2019-06-10 11:13 ` Yoshihiro Shimoda
2019-06-10 11:13 ` Yoshihiro Shimoda
2019-06-10 12:32 ` Christoph Hellwig
2019-06-10 12:32 ` Christoph Hellwig
2019-06-10 18:46 ` Alan Stern
2019-06-10 18:46 ` Alan Stern
2019-06-11 6:41 ` Christoph Hellwig
2019-06-11 6:41 ` Christoph Hellwig
2019-06-11 14:51 ` Alan Stern
2019-06-11 14:51 ` Alan Stern
2019-06-12 7:30 ` Christoph Hellwig
2019-06-12 7:30 ` Christoph Hellwig
2019-06-12 8:52 ` Yoshihiro Shimoda
2019-06-12 8:52 ` Yoshihiro Shimoda
2019-06-12 11:31 ` Christoph Hellwig
2019-06-12 11:31 ` Christoph Hellwig
2019-06-13 4:52 ` Yoshihiro Shimoda
2019-06-13 4:52 ` Yoshihiro Shimoda
2019-06-12 11:46 ` Oliver Neukum
2019-06-12 11:46 ` Oliver Neukum
2019-06-12 12:06 ` Christoph Hellwig [this message]
2019-06-12 12:06 ` Christoph Hellwig
2019-06-12 14:43 ` Alan Stern
2019-06-12 14:43 ` Alan Stern
2019-06-13 7:39 ` Christoph Hellwig
2019-06-13 7:39 ` Christoph Hellwig
2019-06-13 16:57 ` Martin K. Petersen
2019-06-13 16:57 ` Martin K. Petersen
2019-06-13 17:16 ` Alan Stern
2019-06-13 17:16 ` Alan Stern
2019-06-13 18:18 ` Greg KH
2019-06-13 18:18 ` Greg KH
2019-06-13 23:01 ` shuah
2019-06-13 23:01 ` shuah
2019-06-14 14:44 ` Alan Stern
2019-06-14 14:44 ` Alan Stern
2019-06-18 15:28 ` shuah
2019-06-18 15:28 ` shuah
2019-06-19 20:23 ` shuah
2019-06-19 20:23 ` shuah
2019-06-19 21:05 ` Alan Stern
2019-06-19 21:05 ` Alan Stern
2019-06-21 17:43 ` Suwan Kim
2019-06-21 17:43 ` Suwan Kim
2019-06-11 6:49 ` Yoshihiro Shimoda
2019-06-11 6:49 ` Yoshihiro Shimoda
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