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by cleverca22
Tue Jul 27, 2021 6:00 am
Forum: General discussion
Topic: How does raspberry pi boot process knows where the kernel entrypoint is located?
Replies: 2
Views: 181

Re: How does raspberry pi boot process knows where the kernel entrypoint is located?

the kernel.img entry-point is always the very start of the file

so the entry-point is just whatever address kernel.img itself was loaded to
by cleverca22
Tue Jul 27, 2021 5:54 am
Forum: General
Topic: Pico as USB display?
Replies: 35
Views: 1288

Re: Pico as USB display?

Not sure, could DSI be done on the PIO too? DSI operates at up to 500mhz DDR if you dont overclock the pico, your limited to at most (125/2)mhz but it would be iffy, (125/4)mhz would be slightly more stable so 31.25mhz ddr that massively limits your pixel clock, and then you have to pick a res/fps ...
by cleverca22
Mon Jul 26, 2021 10:35 pm
Forum: Troubleshooting
Topic: PI 4B, wont boot, red screen
Replies: 4
Views: 136

Re: PI 4B, wont boot, red screen

Have you performed a Web search to find the meaning of "FATAL error-code 0x80008d0c @ 0x00000006 0x80004152 0x00000000" the 2 numbers starting with an 8 are addresses within the compiled binary you need a symbol file and/or source to get anything useful out of it and without a version#, t...
by cleverca22
Mon Jul 26, 2021 5:27 pm
Forum: Raspberry Pi OS
Topic: how to install a custom kernel
Replies: 6
Views: 240

Re: how to install a custom kernel

did you install the modules with `make modules_install` ?
by cleverca22
Mon Jul 26, 2021 3:39 pm
Forum: Compute Module
Topic: Using DPI interface (RGB 24) on CM4
Replies: 6
Views: 143

Re: Using DPI interface (RGB 24) on CM4

also of note, the official touch screen is DPI based, but there is a DSI->DPI converter board stuck on the back of it
by cleverca22
Mon Jul 26, 2021 1:26 am
Forum: Troubleshooting
Topic: Issue with Latest Hardware Revision 1.4 for 4B boards
Replies: 29
Views: 934

Re: Issue with Latest Hardware Revision 1.4 for 4B boards

I am having issues with the 4B 1.4 in that LibreElec 9.2 just doesn't boot on it. I've tried copying start.elf and fixup.dat from the github zip file, but now the green LED blinks 4 times slowly and then 4 times rapidly; and the Pi doesn't boot. https://www.raspberrypi.org/documentation/configurati...
by cleverca22
Mon Jul 26, 2021 12:21 am
Forum: Troubleshooting
Topic: I click shutdown and red light stays on
Replies: 6
Views: 151

Re: I click shutdown and red light stays on

Ok so what should I do to stop this behaviour? i can think of 3 different things that could cause a difference poweroff vs halt the start4.elf version the eeprom bootloader version and config you would need to compare each of those between the systems, and see how they differ root@pi400:~# vcgencmd...
by cleverca22
Sun Jul 25, 2021 11:26 pm
Forum: Troubleshooting
Topic: I click shutdown and red light stays on
Replies: 6
Views: 151

Re: I click shutdown and red light stays on

This is normal. The Pi does not have the ability to turn off the 5V supply, so the red light remains on. on some models, the red led is tied to a gpio pin, and can be changed from software root@pi4:/sys/class/leds/led1# echo heartbeat > trigger with this, my red led is giving out 2 blinks every sec...
by cleverca22
Sun Jul 25, 2021 11:17 pm
Forum: Troubleshooting
Topic: No ping, no ssh, no http; wired; headless
Replies: 23
Views: 468

Re: No ping, no ssh, no http; wired; headless

UUID's are all right, so thats not it

all i can think of then is to add a noauto to the mount options of /boot, and then try to diagnose what is wrong after it boots
by cleverca22
Sun Jul 25, 2021 10:22 pm
Forum: Troubleshooting
Topic: Isolcpus and Taskset help (LED Matrix)!
Replies: 3
Views: 118

Re: Isolcpus and Taskset help (LED Matrix)!

how is the matrix being driven from the gpio? there may be ways to (ab)use the DPI peripheral to scan the entire matrix at a cost of 0 cpu time edit: found https://learn.adafruit.com/adafruit-rgb-matrix-bonnet-for-raspberry-pi/pinouts, reading ... GPIO5, Red1 GPIO13, Green1 GPIO6, Blue1 GPIO12, Red2...
by cleverca22
Sun Jul 25, 2021 10:12 pm
Forum: Troubleshooting
Topic: No ping, no ssh, no http; wired; headless
Replies: 23
Views: 468

Re: No ping, no ssh, no http; wired; headless

what does "blkid" return for this sd card?
by cleverca22
Sun Jul 25, 2021 10:09 pm
Forum: General
Topic: Current consumption on sleep modes
Replies: 23
Views: 460

Re: Current consumption on sleep modes

I do a fair amount of IoT at present and for most of the battery powered stuff a single core running at 4 or even just 2MHz is more than sufficient - so for the Pico one of the cores is a bit redundant and the 180uA is as you say, a bit much. So I guess the short answer is it wasn't the target. ano...
by cleverca22
Sun Jul 25, 2021 8:21 pm
Forum: General
Topic: Current consumption on sleep modes
Replies: 23
Views: 460

Re: Current consumption on sleep modes

one thing i noticed, is that each of the 6 ram banks has its own power enable flag

at the cost of loosing the contents for a chunk of ram, you can probably get the power usage even lower
by cleverca22
Sun Jul 25, 2021 8:15 pm
Forum: Graphics programming
Topic: pi4 tvout with real kms
Replies: 7
Views: 202

Re: pi4 tvout with real kms

here is a util i wrote to dump all of the relevant registers, and decode some Vec: CM_VECCTL: 0x96 CM_VECDIV: 0x7000 src: 6 enabled: 1 kill: 0 busy: 1 busyd: 0 frac: 0 divisor: 7.000000 pi4 0x7ec13000 61 63 65 76 61 63 65 76 61 63 65 76 61 63 65 76 |acevacevacevacev| 0x7ec13010 61 63 65 76 61 63 65 ...
by cleverca22
Sun Jul 25, 2021 7:36 pm
Forum: HATs and other add-ons
Topic: rpi zero with 18650 Battery hat and OTG functionnality
Replies: 3
Views: 104

Re: rpi zero with 18650 Battery hat and OTG functionnality

As for charging and discharging at the same time, I may have have not explained it correctly. What I meant was, in theory we should be able to charge the batteries while using the rpi because the charging board will supply sufficient current for the device and for the batteries. So they batteries w...
by cleverca22
Sun Jul 25, 2021 7:12 pm
Forum: Graphics programming
Topic: pi4 tvout with real kms
Replies: 7
Views: 202

Re: pi4 tvout with real kms

so anything below 5.10.50 won't have those fixes. gave rpi-update a spin: Linux pi400 5.10.52-v8+ #1439 SMP PREEMPT Thu Jul 22 15:43:49 BST 2021 aarch64 GNU/Linux pi@pi400:~ $ dmesg | grep drm --color -C5 [ 4.855721] bcm2835-isp bcm2835-isp: Loaded V4L2 bcm2835-isp [ 4.863524] bcm2835-codec bcm2835...
by cleverca22
Sun Jul 25, 2021 4:40 pm
Forum: Graphics programming
Topic: pi4 tvout with real kms
Replies: 7
Views: 202

Re: pi4 tvout with real kms

updating things with apt didnt help: pi@pi400:~ $ uname -a Linux pi400 5.10.17-v8+ #1421 SMP PREEMPT Thu May 27 14:01:37 BST 2021 aarch64 GNU/Linux pi@pi400:~ $ dmesg | grep drm -C5 --color [ 4.713414] [vc_sm_connected_init]: start [ 4.720437] [vc_sm_connected_init]: installed successfully [ 4.75375...
by cleverca22
Sun Jul 25, 2021 4:20 pm
Forum: Graphics programming
Topic: pi4 tvout with real kms
Replies: 7
Views: 202

Re: pi4 tvout with real kms

ahh, i was searching the overlay source for tv and vec, but not composite! and i somehow missed the status= override for the vec in the kms overlay [ 4.557159] [drm] Initialized v3d 1.0.0 20180419 for fec00000.v3d on minor 0 [ 4.557706] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac434...
by cleverca22
Sun Jul 25, 2021 5:06 am
Forum: Graphics programming
Topic: pi4 tvout with real kms
Replies: 7
Views: 202

pi4 tvout with real kms

i tried getting ntsc video output working on my pi4 today, with the real kms driver, only to discover that it doesnt work, and puts the gpu into a really weird dual-stack mode the relevant config dtoverlay=vc4-kms-v3d max_framebuffers=2 enable_uart=1 enable_tvout=1 some various shell commands: root@...
by cleverca22
Sun Jul 25, 2021 1:38 am
Forum: Camera board
Topic: Extending PiCam with CSI to HDMI
Replies: 6
Views: 536

Re: Extending PiCam with CSI to HDMI

simplest option, a pi1 board, that does CSI->h264 encoding, then just spit it out ethernet!
by cleverca22
Sat Jul 24, 2021 8:15 pm
Forum: General discussion
Topic: Ertm permission denied
Replies: 2
Views: 96

Re: Ertm permission denied

because bluetooth is a module, you can also just set those options with modprobe.conf instead an example from my system: [clever@amd-nixos:~]$ cat /etc/modprobe.d/debian.conf # These are the standard aliases and dependencies. # This file does not need to be modified. # prevent unusual drivers from a...
by cleverca22
Sat Jul 24, 2021 6:25 pm
Forum: Troubleshooting
Topic: gpu_mem=16 in /boot/config.txt causes bus-errors, panics etc.
Replies: 17
Views: 563

Re: gpu_mem=16 in /boot/config.txt causes bus-errors, panics etc.

some extra info that might help 1: root@pi400:~# vcdbg malloc Pool 0xbef0d278 (3edee784) Malloc pool size=16M (pool=0x3ef0d278-0x3ff7ff2c) 0x3ef0d2a0 = malloc(128K) [call from 0x3ed55772] 0x3ef2d2c0 = malloc(28) [call from 0x3ed1239c] 0x3ef2e000 = malloc(138K) [call from 0x3ec6c868] 0x3ef50c20 = mal...
by cleverca22
Fri Jul 23, 2021 3:22 pm
Forum: Beginners
Topic: Is it possible to boot the Raspberry Pi 4 with arm_freq = 1622MHz and then dynamically increase it?
Replies: 10
Views: 370

Re: Is it possible to boot the Raspberry Pi 4 with arm_freq = 600MHz and then dynamically increase it?

root@pi400:/sys/devices/system/cpu/cpufreq/policy0# cat scaling_available_frequencies 600000 700000 800000 900000 1000000 1100000 1200000 1300000 1400000 1500000 1600000 1700000 1800000 my pi400 already idles at 600mhz by default, with the ability to ramp up to 1.8ghz, in 100mhz steps root@pi400:/s...
by cleverca22
Thu Jul 22, 2021 11:47 pm
Forum: General discussion
Topic: What is that?
Replies: 16
Views: 599

Re: What is that?

oh yeah, and the official display (DSI) wont work on the pi400, no DSI port exposed

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