[BUG] Intel HD Graphic QM57 chipset: Dell U3011 monitor turns to power saving mode

[Keith Packard]

On Sat, 21 Jan 2012 13:56:21 -0500, Mathieu Desnoyers <mathieu.desnoyers at efficios.com> wrote:

> Dell U3011 monitor turns to power saving mode when resolution set to 2560 x 1600
> (intermittent)
> 
> Reproduced with:
> Linux 2.6.38-1-amd64 (Debian kernel)
> Linux 3.1.0-1-amd64  (Debian kernel)
> Linux 3.2.0-1-amd64  (Debian kernel)
> 
> The computer is a Lenovo X201 Tablet (Intel QM57 chipset), on a X200
> docking station. The docking station uses a DisplayPort cable to connect
> to the monitor.  I tried upgrading my Bios from 1.34/1.13 to 1.38/1.14
> (latest), which did not fix the problem. I cannot use anything else
> than DisplayPort in this case to connect the monitor at 2560 x 1600,
> because this resolution requires either the bandwidth provided by a
> dual-link DVI (which I cannot connect in my docking station), or
> DisplayPort.

I use this same monitor, and have run it with an X200 in the past.

Can you capture a dmesg output with the kernel parameter drm.debug=0xe
set? That will let us see the DP link training adventure and see what's
broken. If you can, separate traces of working and non-working tries
would be nice.

And, of course, trying 3.3-rc1 would be helpful as that's what any
test patches would be developed on top of.

-- 
keith.packard at intel.com
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