From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: MT76x2U crashes XHCI driver on AMD Ryzen system
Date: Tue, 26 Feb 2019 11:44:13 +0100
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To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>, Rosen Penev <rosenp@gmail.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
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On Tue, Feb 26, 2019 at 11:34:51AM +0100, Stanislaw Gruszka wrote:
> On Tue, Feb 26, 2019 at 11:05:36AM +0100, Joerg Roedel wrote:
> If sg->offset > PAGE_SIZE is fine then most likely we have problem with
> alignment.

The map_sg implementation in the AMD IOMMU driver uses sg_phys() which
handles the sg->page + sg->offset calculation fine.

> Note hat issue is with dma_map_sg(), switching to dma_map_single()
> by using urb->transfer_buffer instead of urb->sg make things work
> on AMD IOMMU.

On the other hand this points to a bug in the driver, I'll look further
if I can spot something there.

Regards,

	Joerg