[Intel-gfx] i915 DVI resolution regression (3.13.7+)

[Jani Nikula]

On Wed, 09 Apr 2014, Dave Airlie <airlied at gmail.com> wrote:
> On Wed, Apr 9, 2014 at 4:07 PM, Daniel J Blueman <daniel at quora.org> wrote:
>> On 9 April 2014 11:41, Dave Airlie <airlied at gmail.com> wrote:
>>> On Tue, Apr 8, 2014 at 5:32 PM, Daniel J Blueman <daniel at quora.org> wrote:
>>>> On 8 April 2014 15:14, Jani Nikula <jani.nikula at linux.intel.com> wrote:
>>>>> On Tue, 08 Apr 2014, Daniel J Blueman <daniel at quora.org> wrote:
>>>>>> Ville et al,
>>>>>>
>>>>>> It looks like commit e3ea8fa6beaf55fee64bf816f3b8a80ad733b2c2 (or
>>>>>> another commit in 3.13.7) broke modes which require DVI-D dual-link,
>>>>>> eg 2560x1440 with my panel.
>>>>>>
>>>>>> I don't see these modelines in 3.13.7 or later (eg 3.14):
>>>>>>
>>>>>> [     5.582] (II) intel(0): Modeline "2560x1440"x60.0  312.25  2560
>>>>>> 2752 3024 3488  1440 1443 1448 1493 -hsync +vsync (89.5 kHz eP)
>>>>>> [     5.582] (II) intel(0): Modeline "2560x1440"x60.0  312.25  2560
>>>>>> 2752 3024 3488  1440 1443 1448 1493 -hsync +vsync (89.5 kHz eP)
>>>>>> [     5.582] (II) intel(0): Modeline "1920x1200"x59.9  193.25  1920
>>>>>> 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync (74.6 kHz e)
>>>>>>
>>>>>> My monitor is a Dell U2713HM; mobo uses an H87 chipset with i5-4670.
>>>>>
>>>>> By allowing those modes we regressed setups which were not capable of
>>>>> displaying them. So you've got an HDMI->DVI converter?
>>>>>
>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=72961
>>>>
>>>> I am using a dual-link DVI-D to DVI-D cable to this monitor, since I
>>>> previously couldn't get 2560x1440 via HDMI.
>>>
>>> Intel hw has dual-link DVI-D? I'm not sure I've ever seen that, is
>>> this SDVO device or plain DVI-D?
>>
>> It's the DVI-D connector on: https://www.asus.com/Motherboards/H87IPLUS/
>
> The link which says "
>
> Integrated Graphics Processor
> - Supports HDMI with max. resolution 4096 x 2304 @ 24 Hz
> - Supports DVI with max. resolution 1920 x 1200 @ 60 Hz
> - Supports RGB with max. resolution 1920 x 1200 @ 60 Hz
>
> I'm even wondering electrically how a HDMI->dual-link DVI adapter works.

The current assumption is that in the working case, they are really
operated in single-link, with a frequency beyond the single-link DVI
cable spec.

BR,
Jani.



>
> Dave.

-- 
Jani Nikula, Intel Open Source Technology Center