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by alanbork
Sun Jan 31, 2021 3:43 pm
Forum: Beginners
Topic: Is there a more up to date source of documentation than raspberrypi.org/documentation/ ?
Replies: 11
Views: 575

Re: Is there a more up to date source of documentation than raspberrypi.org/documentation/ ?

This does seem to highlight the real need to an independent documentation source, community sourced like Wikipedia.
by alanbork
Tue Jan 26, 2021 11:53 pm
Forum: Beginners
Topic: Is there a more up to date source of documentation than raspberrypi.org/documentation/ ?
Replies: 11
Views: 575

Is there a more up to date source of documentation than raspberrypi.org/documentation/ ?

I'm constantly running into undocumented issues with the video firmware or configuration particularly for the pi4. Given it's length you'd think the documentation at https://www.raspberrypi.org/documentation/ would be authoritative , but it's far from that. Is there a better resource? I'm not agains...
by alanbork
Tue Jan 26, 2021 11:37 pm
Forum: Troubleshooting
Topic: Pi4 and config_hdmi_boost working or not? 4k TV says no signal
Replies: 6
Views: 364

Re: Pi4 and config_hdmi_boost working or not? 4k TV says no signal

Turns out 4k60 is not supported on KMS. Have to use FKMS for that.
by alanbork
Tue Jan 26, 2021 12:39 am
Forum: Troubleshooting
Topic: Pi4 and config_hdmi_boost working or not? 4k TV says no signal
Replies: 6
Views: 364

Re: Pi4 and config_hdmi_boost working or not? 4k TV says no signal

I'm not so sure about having group 1 mode 4 (720p) but have hdmi_enable_4kp60=1 when you aren't in 4k mode that way I can boot up and poke around (such as to see what modes are available according to tvservice for instance) even if 4k60 doesn't work. I do not currently have access to test the TVs I...
by alanbork
Mon Jan 25, 2021 11:19 pm
Forum: Graphics programming
Topic: bad tearing on the simplest DRM+GBM program
Replies: 13
Views: 692

Re: bad tearing on the simplest DRM+GBM program

i had also gone over every combination of settings back in late december, and found that no combination entirely eliminated it, but some where better then others https://www.raspberrypi.org/forums/viewtopic.php?f=140&t=295740 the thread also has directions on how to undo rpi-update, and get bac...
by alanbork
Sun Jan 24, 2021 5:57 pm
Forum: Beginners
Topic: Send keypress events to my computer
Replies: 2
Views: 89

Re: Send keypress events to my computer

See this https://randomnerdtutorials.com/raspber ... board-hid/ for some examples. Still not 100% sure it's supported on the current releases, though. Haven't gotten a chance to try it myself.
by alanbork
Sun Jan 24, 2021 5:56 pm
Forum: Automation, sensing and robotics
Topic: Emulating mouse inputs
Replies: 6
Views: 6055

Re: Emulating mouse inputs

I just found this, which seems to be what I need for keyboard, but also dated with comments that it doesn't work anymore? Also, still can't find full details on how to simulate the mouse. Is there any more official source of documentation or example code? https://randomnerdtutorials.com/raspberry-pi...
by alanbork
Sun Jan 24, 2021 1:06 am
Forum: Automation, sensing and robotics
Topic: Emulating mouse inputs
Replies: 6
Views: 6055

Re: Emulating mouse inputs

I'm also interested in how to make my piZero act like a mouse (or keyboard) when plugged into my desktop so I can send keystrokes or mouse vectors. There's this adafruit article but aside from hinting that it's possible it's a dead end as far as pretending to be either a mouse or keyboard. https://l...
by alanbork
Sun Jan 24, 2021 12:57 am
Forum: Graphics programming
Topic: bad tearing on the simplest DRM+GBM program
Replies: 13
Views: 692

Re: bad tearing on the simplest DRM+GBM program

but if you switch over to the proper vc4-kms-v3d driver, that vsync irq goes directly to the arm core and linux then it just updates the display list directly (no translating drm->dispmanx->displaylist), and swaps the frame over that sounds great and I'll give that a try with the latest kms driver,...
by alanbork
Sat Jan 23, 2021 11:30 pm
Forum: Graphics programming
Topic: bad tearing on the simplest DRM+GBM program
Replies: 13
Views: 692

Re: bad tearing on the simplest DRM+GBM program

Tearing is a long-standing known issue with the RPI 4, which has been described as "very difficult to fix". If you search the forums for "tearing" you will find many references. It's difficult to fix with the vc4-fkms-v3d driver. With the full KMS vc4-kms-v3d driver it works fin...
by alanbork
Sat Jan 23, 2021 11:23 pm
Forum: Graphics programming
Topic: bad tearing on the simplest DRM+GBM program
Replies: 13
Views: 692

Re: bad tearing on the simplest DRM+GBM program

Tearing is a long-standing known issue with the RPI 4, which has been described as "very difficult to fix". If you search the forums for "tearing" you will find many references. at the hardware level, its fairly simple first, you have the display list memory, uint32_t[4096], 7 s...
by alanbork
Sat Jan 23, 2021 5:27 am
Forum: Graphics programming
Topic: bad tearing on the simplest DRM+GBM program
Replies: 13
Views: 692

bad tearing on the simplest DRM+GBM program

I'm wondering why I'm seeing screen tearing on my pi4 with an extremely simple program that merely clears the buffer to and then flips it. Here's a video of the tearing: https://www.youtube.com/watch?v=saGxWnEtkzU here's the code (mostly unmodified drm-gbm.c; all I added was alternating between blac...
by alanbork
Fri Jan 08, 2021 10:13 pm
Forum: Advanced users
Topic: Pi4 HDMI cable suggestions for 4k?
Replies: 3
Views: 201

Re: Pi4 HDMI cable suggestions for 4k?

It sounds like some people are having better luck with the canakit one, which you can actually get from amazon unlike the official pi cable?
by alanbork
Fri Jan 08, 2021 8:26 pm
Forum: Troubleshooting
Topic: 4k@60Hz not working with vc4-fkms-v3d
Replies: 1
Views: 120

Re: 4k@60Hz not working with vc4-fkms-v3d

alexsh wrote: . I also tried with a CANAKit cable but video would just cut out every 5 seconds.

so you get no video with two cables and consistent but intermittent video with the 3rd?
by alanbork
Wed Dec 23, 2020 6:15 am
Forum: Advanced users
Topic: Pi4 HDMI cable suggestions for 4k?
Replies: 3
Views: 201

Re: Pi4 HDMI cable suggestions for 4k?

Good to know! It seems like it's not sold on amazon, though? The S&H from the official resellers is killer.

The only thing that matches on amazon looks a bit shady:

https://www.amazon.com/Waveshare-Offici ... B07YG1C73N
by alanbork
Wed Dec 23, 2020 2:29 am
Forum: Troubleshooting
Topic: Pi4 and config_hdmi_boost working or not? 4k TV says no signal
Replies: 6
Views: 364

Re: Pi4 and config_hdmi_boost working or not? 4k TV says no signal

I am still having problems. It almost never works. I've now tried too cables too. What cable are you using? This one perhaps?

https://www.canakit.com/official-micro- ... efpid=4651

are you using a short one?
by alanbork
Wed Dec 23, 2020 2:25 am
Forum: Advanced users
Topic: Pi4 HDMI cable suggestions for 4k?
Replies: 3
Views: 201

Pi4 HDMI cable suggestions for 4k?

Does anybody have a suggestion for a HDMI cable they know works for 4k at 60hz on the pi4? I can find lots of cables online that say 4k60 supported, but then for those with reviews there are often people saying they don't work (though typically on more mainstream hardware like the apple tv).
by alanbork
Sun Dec 13, 2020 3:14 am
Forum: Troubleshooting
Topic: How many people have gotten 4k60p (3840x2160x60hz) to work with the Pi4? Not me.
Replies: 2
Views: 208

Re: How many people have gotten 4k60p (3840x2160x60hz) to work with the Pi4? Not me.

why all the extra settings? just using hdmi_enable_4kp60=1 should be enough for a single monitor. then select the screen rez in screen config. for duel monitor it will only do 30. well I do use my pi for more than just 4k stuff. I included the whole thing in case there were settings that were relev...
by alanbork
Sun Dec 13, 2020 1:28 am
Forum: Troubleshooting
Topic: How many people have gotten 4k60p (3840x2160x60hz) to work with the Pi4? Not me.
Replies: 2
Views: 208

How many people have gotten 4k60p (3840x2160x60hz) to work with the Pi4? Not me.

I'm trying to get aPi4B (purchased right when they were launched) to work at 4k resolution and 60hz refresh. But the best I can consistently get is 4k30p. I'm wondering if anybody has had success with this, or if the hardware is marginal? I've tested two displays and neither work. The PC monitor I'v...
by alanbork
Sun Dec 13, 2020 1:07 am
Forum: Beginners
Topic: HDMI for 3840x2160 4K monitor cann't be installed
Replies: 1
Views: 227

Re: HDMI for 3840x2160 4K monitor cann't be installed

Did you ever get this to work?
by alanbork
Sun Dec 13, 2020 1:03 am
Forum: Troubleshooting
Topic: 4k60p display issue (DRM VC4 driver crash / backtrace)
Replies: 5
Views: 497

Re: 4k60p display issue (DRM VC4 driver crash / backtrace)

Did you ever figure this out?
by alanbork
Thu Dec 03, 2020 3:38 pm
Forum: Troubleshooting
Topic: Pi4 and config_hdmi_boost working or not? 4k TV says no signal
Replies: 6
Views: 364

Pi4 and config_hdmi_boost working or not? 4k TV says no signal

The official docs say that config_hdmi_boost doesn't work on the pi4 but I keep on seeing people suggest using it, and even reporting success. Is that just left over knowledge from the pi3 and earlier days or is it now supported? As you might expect I'm asking because I have a TV (LG UK6300) that do...
by alanbork
Tue Dec 01, 2020 7:42 pm
Forum: Troubleshooting
Topic: impossible to power off HDMI display [FKMS]
Replies: 4
Views: 188

Re: impossible to power off HDMI display [FKMS]

aBUGSworstnightmare wrote: YOu can use KMS with latest 5.10 kernel ... so why are you stucked with FKMS?
are you saying there's a way to turn off (and back on) the HDMI output if you use KMS?

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