From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= <roger.pau@citrix.com>
Subject: Re: Commit dd6d87 breaks serial console
Date: Mon, 14 Jul 2014 19:52:00 +0200
Message-ID: <53C418C0.805@citrix.com>
References: <53C40054.8080400@citrix.com> <53C40468.8030401@citrix.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>, xen-devel <xen-devel@lists.xen.org>, Jan Beulich <JBeulich@suse.com>, "Tim (Xen.org)" <tim@xen.org>, Yang Zhang <yang.z.zhang@intel.com>, Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>
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On 14/07/14 18:25, Andrew Cooper wrote:
> On 14/07/14 17:07, Roger Pau Monn=E9 wrote:
>> Hello,
>>
>> The following commit:
>>
>> commit dd6d87a4fcc8350c752e389abb3bcd8479c37555
>> Author: Jan Beulich <jbeulich@suse.com>
>> Date:   Fri Jun 20 10:26:37 2014 +0200
>>
>>     VT-d: drop redundant calls to invalidate_sync()
>>
>>     The call tree iommu_flush_iec_index() -> __iommu_flush_iec() already
>>     invokes invalidate_sync(). Removing the superfluous instances at once
>>     allows the function to become static.
>>
>>     Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>     Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>     Acked-by: Yang Zhang <yang.z.zhang@intel.com>
>>
>> Breaks serial console on my box, this is all the output I get with this =

>> commit applied:
> =

> Are you sure you have bisected this correctly?
> =

> Unless there is some hardware side-effect of issuing two qinvalidate
> wait descriptors back-to-back, the change still looks to be good. =

> Alternately, are we missing a hardware erratum for your system?

Just for the record, setting iommu=3Dno-intremap solves the problem, so
I'm quite sure I've bisected it right. This is on a Xeon W3550, I can
provide whatever other hardware information is needed.

Roger.