Re: Interlaced resolutions hang the desktop

From: "Christian König" <christian.koenig@amd.com>
To: Alberto Salvia Novella <es20490446e@gmail.com>
Cc: alexander.deucher@amd.com,
	"Christian König" <ckoenig.leichtzumerken@gmail.com>,
	linux-fbdev@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	benh@kernel.crashing.org
Subject: Re: Interlaced resolutions hang the desktop
Date: Wed, 31 Mar 2021 08:44:14 +0200	[thread overview]
Message-ID: <3d3563f3-f093-f293-e237-b87306a4cede@amd.com> (raw)
In-Reply-To: <CAHJvkbvkwAw2-pRo=rvnB98XxgtNCE-QAzv4HZ-KceH-vZkKoA@mail.gmail.com>

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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@amd.com <mailto:christian.koenig@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@gmail.com
>>     <mailto:ckoenig.leichtzumerken@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@amd.com <mailto:christian.koenig@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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