From: Stanislaw Gruszka <sgruszka@redhat.com>
To: Rosen Penev <rosenp@gmail.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Lorenzo Bianconi <lorenzo.bianconi@redhat.com>,
linux-wireless <linux-wireless@vger.kernel.org>,
Samuel Sieb <samuel@sieb.net>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, jan.viktorin@gmail.com
Subject: Re: MT76x2U crashes XHCI driver on AMD Ryzen system
Date: Tue, 12 Mar 2019 08:13:14 +0100 [thread overview]
Message-ID: <20190312071314.GB2483@redhat.com> (raw)
In-Reply-To: <20190311084319.GA3310@redhat.com>
On Mon, Mar 11, 2019 at 09:43:19AM +0100, Stanislaw Gruszka wrote:
> > > However after fixing that mt76usb still did not work. To make things
> > > work we had to change rx frag size from 2048 to PAGE_SIZE and change
> > > virt_to_head_page() to virt_to_page() when setting SG's.
> >
> > > I think I understand why first change was needed. If we do 2 separate
> > > dma maps of 2 different buffers in single page i.e (PAGE + off=0
> > > and PAGE + off=2048) it causes problem. So either map_sg() return
> > > error which mt76usb does not handle correctly or there is issue
> > > in AMD IOMMU because two dma maps use the same page.
>
> Any comment on that? Is fine or not to do 2 or more dma mappings
> within the same single page on AMD IOMMU? If not, is there any
> mechanism for drivers to find out about this limitation to prevent
> to prepare wrong SG buffers?
FTR: it was confirmed by Jan (bug reporter) the 2 or more dma mappings
within single page works with AMD IOMMU. Most likely it was needed
previously to workaround this sg->offset problem until proper fix to
AMD IOMMU was applied.
Stanislaw
prev parent reply other threads:[~2019-03-12 7:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAKxU2N9o5WeUwFMUwwXKHaPj7R+oiSKV1c2n8RtXwGNZRtw5Sw@mail.gmail.com>
[not found] ` <CAJ0CqmVNF83bWgc+LSQ3_i=zfp-sXC5Nf=nKfqB3SWa8r7sKdQ@mail.gmail.com>
[not found] ` <83A1D243-9073-48D1-9F26-5A2581DCB829@gmail.com>
[not found] ` <CAJ0CqmUgPWNJtCW4Q__sOtB8w-YtwW+uZy7crxMNrmSgQ6OFyA@mail.gmail.com>
[not found] ` <1547404075.1582.0@smtp.gmail.com>
[not found] ` <CAJ0CqmU7k5i26g7dGPxNdts7Gm67W6qNsr4vYuW05ugsEF1ohw@mail.gmail.com>
[not found] ` <CAKxU2N-+CTaRdJMFVRdozJ5TTpN+_4thiDRBJBFq8gGtuRVYvA@mail.gmail.com>
[not found] ` <20190114091841.GA23045@localhost.localdomain>
[not found] ` <CAKxU2N8ioMszBCyQcH7CVhgBdW4aj7yZ+kYQe14DCV5OSAnxrg@mail.gmail.com>
[not found] ` <20190115090400.GA2267@localhost.localdomain>
2019-02-18 14:37 ` MT76x2U crashes XHCI driver on AMD Ryzen system Stanislaw Gruszka
2019-02-18 15:15 ` Lorenzo Bianconi
2019-02-18 17:01 ` Robin Murphy
2019-02-19 11:08 ` Stanislaw Gruszka
2019-02-26 10:05 ` Joerg Roedel
2019-02-26 10:34 ` Stanislaw Gruszka
2019-02-26 10:44 ` Joerg Roedel
2019-02-26 11:24 ` Stanislaw Gruszka
2019-02-28 9:04 ` Stanislaw Gruszka
2019-02-28 10:42 ` Stanislaw Gruszka
2019-02-28 12:19 ` Stanislaw Gruszka
2019-02-28 13:40 ` Joerg Roedel
2019-03-04 7:10 ` Stanislaw Gruszka
2019-03-04 7:20 ` Rosen Penev
2019-03-11 8:43 ` Stanislaw Gruszka
2019-03-11 9:03 ` [PATCH] iommu/amd: fix sg->dma_address for sg->offset bigger than PAGE_SIZE Stanislaw Gruszka
2019-03-11 15:47 ` Alexander Duyck
2019-03-12 7:08 ` Stanislaw Gruszka
2019-03-12 15:18 ` Alexander Duyck
2019-03-13 9:03 ` [PATCH v2] " Stanislaw Gruszka
2019-03-18 10:17 ` Joerg Roedel
2019-03-12 7:13 ` Stanislaw Gruszka [this message]
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