11:16 <Advancel> Hi everybody. I'm trying to open second framebuffer with 6.1.9 linux or Linux 6>= on Allwinner A13(sun5i). I added second framebuffer entry to DTS but it does not recognize. Also if i delete the first framebuffer entry it goes to second and opens it as fb0

14:26 <Advancel> is there anybody online this channel? I asked a question couple hours ago.

14:29 <apritzel> advancel: 114 people ;-) , but I am afraid you need to be more patient and consider time zones, since your question was somewhat special

14:30 <apritzel> advancel: you can drop off if you like and check the logs later (check the topic for a link)

14:32 <Advancel> Thanks for reminding me about the time zone issue. I completely forgot it.

14:35 <apritzel> Also many people are only active outside of their working hours. I'd give it a day ...

14:38 <mripard> advancel: what do you mean by "opening a second framebuffer" ?

14:42 <Advancel> mripard: Just simple framebuffer that addressed at some region of memory and it will use pipe 1 and that framebuffer will be Yuv format so i can get output from VPU directly with another framebuffer.

14:44 <Advancel> mripard: Because problem is A13 does not have G2D accelerator. So video performance is poor on default layer

14:44 <mripard> what are you calling a framebuffer then?

14:45 <Advancel> mripard: How can i connect to the Pipe 1 without using framebuffer?

14:45 <mripard> I don't know, it's still not clear to me what you are calling a framebuffer

14:47 <Advancel> mripard: Okay more reproducing then. Allwinner A13's DEBE has 4 layers and 2 pipes. We can use only 1 layer and 1 pipe on mainline Linux

14:48 <mripard> no

14:49 <Advancel> mripard: I'm trying to use this second pipe for video encoding. So i need to open simple frame buffer for it. Like /dev/fb1

14:49 <mripard> You can use all 4 layers and both pipes.

14:49 <mripard> alright, so by "framebuffer", you mean /dev/fb* ?

14:49 <Advancel> mripard: Yes

14:49 <mripard> use KMS then

14:49 <mripard> it'll work

14:50 <Advancel> mripard: Okay now your turn :) Can you explain more? ofc if you have time...

14:50 <mripard> sure :)

14:51 <mripard> /dev/fb* is a userspace API called fbdev

14:51 <mripard> your question was confusing because simple framebuffer is an fbdev driver

14:51 <mripard> and a framebuffer is also usually just the buffer in memory storing the frame

14:52 <mripard> so there was like 3 different concepts mentioned in your question, none of them being related to each other

14:52 <mripard> anyway

14:52 <mripard> fbdev support in Linux has been deprecated of another API for close to a decade now?

14:52 <mripard> the "new" graphics API is called KMS

14:53 <mripard> so the answer to your question is "don't use the legacy, deprecated API, the new API will be able to do what you want just fine"

14:57 <advancel> mripard: Okay thank you so much. To be more clear; In old sunxi3.4 linux i can decode the video with cedar and send to the other framebuffer without any pixel format conversion. The performance was insane. Now i'm trying to catch same performance in Mainline. This is the my goal for now.

15:15 <MoeIcenowy> yes you need to use KMS

15:15 <MoeIcenowy> fbdev never gains support for multiple planes

15:16 <MoeIcenowy> on Allwinner it's done by using /dev/disp, a proprietary device file

15:16 <MoeIcenowy> on mainline kernel, it's the mainline way, KMS

15:27 <advancel> Also what do you think about this issue that G2Dless A13 poor decoding performance?

15:29 <advancel> MoeIcenowy: Thanks to you to by the way.