Interlaced resolutions hang the desktop

[Alberto Salvia Novella]

24fps is intended for video only. Anything interactive at 24fps, as just
moving the mouse around, is extremely choppy.

No way anyone would prefer that over an interlaced resolution or a lower
resolution. That is, by far, the worst option.

Just try it on your screen, set it to 24Hz or alike, and tell me your
experience. You can't even tell where the mouse is going to go.

On Wed, 31 Mar 2021 at 08:44, Christian König <christian.koenig at amd.com>
wrote:

> Hi Alberto,
>
> well a frame rate of 24Hz is perfectly reasonable for a TV and desktop
> usage.
>
> This is probably caused by the TVs limited HDMI bandwidth and a refresh
> rate of 30/25 Hz for the interlaced mode isn't much better either.
>
> Regards,
> Christian.
>
> Am 30.03.21 um 22:59 schrieb Alberto Salvia Novella:
>
> The frame-rate at 24Hz is extremely poor for normal desktop usage.
>
> If the highest resolution, aka 1080p, uses that refresh rate then the
> desktop will default to that frame-rate.
>
> Other progressive modes don't exhibit any issue.
>
> On Tue, 30 Mar 2021 at 18:26, Christian König <christian.koenig at amd.com>
> wrote:
>
>> Hi Alberto,
>>
>> I think the driver should only support resolutions that are *progressive*,
>> but also at least of *50Hz*.
>>
>>
>> Why do you think so?, the 24Hz resolution seems to be the native one of
>> the display.
>>
>> Regards,
>> Christian.
>>
>> Am 30.03.21 um 17:37 schrieb Alberto Salvia Novella:
>>
>> This is why I'm using interlaced:
>>
>> $ *xrandr*
>> Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
>> DisplayPort-0 disconnected (normal left inverted right x axis y axis)
>> HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis
>> y axis) 16mm x 9mm
>>    1920x*1080i*    60.00*+  50.00    59.94
>>    1920x1080     *24.00*    23.98
>>    1280x*720*      60.00    50.00    59.94
>>    1024x768      75.03    70.07    60.00
>>    832x624       74.55
>>    800x600       72.19    75.00    60.32    56.25
>>    720x576       50.00
>>    720x576i      50.00
>>    720x480       60.00    59.94
>>    720x480i      60.00    59.94
>>    640x480       75.00    72.81    66.67    60.00    59.94
>>    720x400       70.08
>> DVI-0 disconnected (normal left inverted right x axis y axis)
>>
>> I think the driver should only support resolutions that are *progressive*,
>> but also at least of *50Hz*.
>>
>> On Tue, 30 Mar 2021 at 15:41, Christian König <
>> ckoenig.leichtzumerken at gmail.com> wrote:
>>
>>> Mhm, no idea why an interlaced resolution would cause a crash. Maybe
>>> some miscalculation in the display code.
>>>
>>> But apart from that if you just connected your PC to a TV I also
>>> wouldn't recommend using an interlaced resolution in the first place.
>>>
>>> See those resolutions only exists for backward compatibility with analog
>>> hardware.
>>>
>>> I think we would just disable those modes instead of searching for the
>>> bug.
>>>
>>> Regards,
>>> Christian.
>>>
>>> Am 30.03.21 um 11:07 schrieb Alberto Salvia Novella:
>>>
>>> I guessed so.
>>>
>>> The GPU is a Radeon HD5870, and the screen is an old Telefunken TV
>>> (TLFK22LEDPVR1).
>>>
>>> Since my real display got into repair I used this TV meanwhile, and to
>>> my surprise it froze the system.
>>>
>>> On Tue, 30 Mar 2021 at 10:15, Christian König <christian.koenig at amd.com>
>>> wrote:
>>>
>>>> Hi Alberto,
>>>>
>>>> well what hardware do you have?
>>>>
>>>> Interlaced resolutions are not used any more on modern hardware, so
>>>> they
>>>> are not well tested.
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>> Am 30.03.21 um 10:04 schrieb Alberto Salvia Novella:
>>>> > The entire desktop hangs after some minutes when using the module
>>>> > "radeon" with an interlaced resolution.
>>>> >
>>>> > Easier to trigger by playing a video on Firefox, at least on
>>>> kwin_x11.
>>>> > Wayland didn't exhibit the problem.
>>>> >
>>>> > Other display drivers, from different computers I have tried, didn't
>>>> > allow those interlaced resolutions all together. It seems they know
>>>> > there will be problems.
>>>>
>>>>
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>>>
>>
>
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