From: Thomas Zimmermann <tzimmermann@suse.de>
To: Wang Yugui <wangyugui@e16-tech.com>
Cc: Jocelyn Falempe <jfalempe@redhat.com>,
dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: mgag200 broken on kernel-6.0-rc3 on DELL/T620
Date: Wed, 14 Sep 2022 17:41:50 +0200 [thread overview]
Message-ID: <9e801194-ea74-7298-c08c-de5eeb7444e6@suse.de> (raw)
In-Reply-To: <20220914225809.763F.409509F4@e16-tech.com>
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Hi
Am 14.09.22 um 16:58 schrieb Wang Yugui:
> Hi,
>
>> (cc: Jocelyn)
>>
>> Hi
>>
>> Am 14.09.22 um 10:29 schrieb Wang Yugui:
>>> Hi,
>>>
>>>
>>>> Hi
>>>>
>>>> Am 13.09.22 um 17:15 schrieb Wang Yugui:
>>>> [...]
>>>>>>>
>>>>>>> so I tried to revert patch of mgag200 driver in batch of 2 or 3, the I
>>>>>>> noticed the patch 'Subject: drm/mgag200: Remove special case for G200SE
>>>>>>> with <2 MiB' and then tried this dirty fix.
>>>>>>
>>>>>> Oh, great work! Thank you. From looking at the screenshot that you provided, it seems as if the 24-bit mode setting is broken. I'm not sure why the G200SE workaround applies to a G200ER, but we'll see.
>>>>>
>>>>> I tested 'preferred_depth = 32' too. it works on T630 too.
>>>>>
>>>>> so both 16 and 32 work, but 24 failed on DELL/T630.
>>>>
>>>> I tried on my test machine with a 5.19 kernel and found that 32-bit and 24-bit pixels work, but 16-bit looks incorrect.
>>>>
>>>> What are the results if you boot your kernel 5.19.3 with the parameter video=1024x768-24? This should enable 24-bit pixels.
>>>>
>>>> How does video=1024x768-16 look with the 5.19 kernel?
>>>
>>> test result here
>>> kernel 5.19.3 & video=1024x768-24
>>> dell/T620/centos-8.5 broken
>>> dell/T630/centos-7.9 broken
>>
>> I assume that Centos 7 and 8 have fairly old kernels? So it's been a long-standing bug.
>
> We install kernel 5.19.3/5.15.67 into Centos 7 and 8.
> default it work well. broken just when 'video=1024x768-24', so it may
> not a long-standing bug.
I don't quite understand. Does 'video=1024x768-24' work with 5.15.67?
>
>> 24-bit works on my G200HE and G200 test machines. Maybe the G200ER has a bug.
>>
>> When I try 16-bit depth, the display works, but is way too dark. No fiddling with the LUT tables fixes this. It's 90s hardware, so it should support 16-bit framebuffers well, but there's no obvious bug to be seen.
>>
>> I guess, we could remove 16 and 24 bit support for now if nothing else helps.
>
>
> maybe better if we revert 73f54d5d9682 (drm/mgag200: Remove special case
> for G200SE with <2 MiB)
>
> because there is no test result on device G200_SE
We cannot revert it directly, but tomorrow I'll send you a patch that
should restore the old behavior.
Best regards
Thomas
>
> static unsigned int mgag200_preferred_depth(struct mga_device *mdev)
> {
> if (IS_G200_SE(mdev) && mdev->vram_fb_available < (2048*1024))
> return 16;
> else
> return 32;
> }
>
> Best Regards
> Wang Yugui (wangyugui@e16-tech.com)
> 2022/09/14
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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next prev parent reply other threads:[~2022-09-14 15:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220902135242.2447.409509F4@e16-tech.com>
2022-09-05 6:57 ` mgag200 broken on kernel-6.0-rc3 on DELL/T620 Thomas Zimmermann
2022-09-07 4:16 ` Wang Yugui
2022-09-07 6:47 ` Thomas Zimmermann
2022-09-07 7:38 ` Wang Yugui
2022-09-07 7:55 ` Thomas Zimmermann
2022-09-07 8:47 ` Wang Yugui
2022-09-07 9:18 ` Thomas Zimmermann
2022-09-13 8:34 ` Thomas Zimmermann
2022-09-13 14:25 ` Wang Yugui
2022-09-13 14:44 ` Thomas Zimmermann
2022-09-13 15:15 ` Wang Yugui
2022-09-14 7:59 ` Thomas Zimmermann
2022-09-14 8:29 ` Wang Yugui
2022-09-14 14:36 ` Thomas Zimmermann
2022-09-14 14:58 ` Wang Yugui
2022-09-14 15:41 ` Thomas Zimmermann [this message]
2022-09-14 16:25 ` Wang Yugui
2022-09-15 12:54 ` Thomas Zimmermann
2022-09-15 14:41 ` Wang Yugui
2022-09-20 7:57 ` Thomas Zimmermann
2022-09-20 9:02 ` Wang Yugui
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