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by cleverca22
Thu Sep 23, 2021 3:36 am
Forum: General discussion
Topic: Divide instruction missing on Pi4 aarch32?
Replies: 5
Views: 64

Re: Divide instruction missing on Pi4 aarch32?

udiv/sdiv are optional in ARMv7 so gcc doesn't emit those instructions. A kernel targeting ARMv7 can patch the function call to use those instructions if available. ahhh, that would explain why i see options in the linux build, about linux patching its own division stuff at boot time [root@nixos:~]...
by cleverca22
Thu Sep 23, 2021 3:20 am
Forum: General discussion
Topic: Divide instruction missing on Pi4 aarch32?
Replies: 5
Views: 64

Re: Divide instruction missing on Pi4 aarch32?

when i decompiled an arm32 binary, i can see that the functions behind division, are doing the entire division in software, no opcode available

perhaps arm32 just doesnt give you access to the division opcode, ever?
by cleverca22
Thu Sep 23, 2021 2:47 am
Forum: Camera board
Topic: Gun chronograph
Replies: 5
Views: 274

Re: Gun chronograph

125m/s is 450km/h(!) -- as said the modification of pellet is definitely not something one wants to do when trying to hit a distant target, but for pure speed measurement increase as here bullet modification is an option. in my area of canada, you dont need a license for any airgun under ~150 meter...
by cleverca22
Thu Sep 23, 2021 2:31 am
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

Hmm, most Linux kernels are now relying of devicetree? So an open booter will need devicetree support. I understand where and why now. with my current design, i'm building LK in rpi2-test mode, to create a custom baremetal kernel, that acts as a bootloader to run linux it is using device-tree to ma...
by cleverca22
Thu Sep 23, 2021 2:20 am
Forum: Advanced users
Topic: raspberry pi 3b+ lowering power consumption to absolute minimum
Replies: 3
Views: 125

Re: raspberry pi 3b+ lowering power consumption to absolute minimum

just as another data-point, i have a pi2 idling at 0.32A currently, which comes to around 1.6 watts

if you dont need the cpu power, you could maybe switch to an older model?
by cleverca22
Thu Sep 23, 2021 1:40 am
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

[0;root@nixos: ~root@nixos:~]# [ 440.175167] reboot: Restarting system done platform early init 0.162114 [SDRAM:sdram_init]: (0) SD_CS = 0x794200 0.291937 [SDRAM:selftest]: Self test successful! press X to stop autoboot and go into xmodem mode... wait result: -13 10.358288 [EMMC:restart_controller]...
by cleverca22
Wed Sep 22, 2021 10:37 pm
Forum: Troubleshooting
Topic: Serial port receiving wrong characters
Replies: 4
Views: 116

Re: Serial port receiving wrong characters

do you have a logic analyzer or scope?
by cleverca22
Wed Sep 22, 2021 10:29 pm
Forum: Bare metal, Assembly language
Topic: pico like bootloader for pi zero
Replies: 8
Views: 237

Re: pico like bootloader for pi zero

With raspberry pi pico it will be easy to made at low frame rate (i suppose 10fps could be obtained), but not the "save data/video" feature, so i suppose i had to dump samples and process them offline). With raspberry pi zero, i had the power, but i hace to pay the high os loading time an...
by cleverca22
Wed Sep 22, 2021 6:12 am
Forum: Networking and servers
Topic: Site won't load SVG Files
Replies: 2
Views: 105

Re: Site won't load SVG Files

https://ikev.in/icons/wordpress.svg this URL returns a 404

your icons just arent at the path you expect them to be at

you can see it very clearly, if you just hit f12, click the network tab, and then refresh the page
by cleverca22
Wed Sep 22, 2021 6:05 am
Forum: Troubleshooting
Topic: Serial port receiving wrong characters
Replies: 4
Views: 116

Re: Serial port receiving wrong characters

it might be https://github.com/raspberrypi/firmware/issues/1618

does the problem still happen if you add "dtoverlay=disable-bt" to config.txt?

you should also always use /dev/serial0 on the pi end, the above command will change which port is used, but serial0 always points to the right one
by cleverca22
Wed Sep 22, 2021 4:05 am
Forum: Troubleshooting
Topic: raspberry pi4b has KVM acceleration but can not be used in virtual machines
Replies: 5
Views: 145

Re: raspberry pi4b has KVM acceleration but can not be used in virtual machines

look closer
you just said aarch64 and arm, but the error says x86_64

and youve edited the original post to claim it was always aarch64

was that a typo? what is the real error?
by cleverca22
Wed Sep 22, 2021 2:52 am
Forum: Troubleshooting
Topic: raspberry pi4b has KVM acceleration but can not be used in virtual machines
Replies: 5
Views: 145

Re: raspberry pi4b has KVM acceleration but can not be used in virtual machines

kvm can only be used to accelerated a compatible cpu arch
laikee wrote:
Tue Sep 21, 2021 4:58 pm
qemu-system-x86_64: -append root=/dev/vda mem=768M: unsupported machine type
x86_64 is not a compatible ISA, so kvm can never accelerate that on an rpi
by cleverca22
Wed Sep 22, 2021 2:44 am
Forum: General discussion
Topic: No more Rpi laptops?
Replies: 43
Views: 1268

Re: No more Rpi laptops?

Gamers screens with 120Hz+? there are 2 separate frequencies at play 120hz, is the refresh rate of the lcd panel, and depending on the tech, it may have zero flicker, just switching between states for each frame but, separately from that, is the pwm rate for the backlight, which will be a much high...
by cleverca22
Wed Sep 22, 2021 2:23 am
Forum: Bare metal, Assembly language
Topic: pico like bootloader for pi zero
Replies: 8
Views: 237

Re: pico like bootloader for pi zero

Is there a sort of c/c++ (micropython not interested) boot loader for raspberry pi (w) to use it like it was some kind of pumped raspberry pi pico? the pi0 already has a bootloader in its maskrom, just like the pico does if you turn on a pi0 without any SD card, it will go into rpiboot mode, and yo...
by cleverca22
Tue Sep 21, 2021 9:33 pm
Forum: Gaming
Topic: Seeking interest and support in a game designed for Rpi
Replies: 106
Views: 10445

Re: Seeking interest and support in a game designed for Rpi

that was a spammer copy/pasting my original msg, so he could get by the 1st-post moderation
by cleverca22
Tue Sep 21, 2021 5:32 pm
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

https://github.com/librerpi/lk-overlay/blob/master/platform/bcm28xx/v3d/v3d.c this is the source ive been using lately, for the 3d core but the pi4 changed how some parts of the 3d core work, and i'm currently in the dark on exactly what changed but the pi4 3d core, isnt even supported by the blob!,...
by cleverca22
Tue Sep 21, 2021 6:03 am
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

0.159673 [SDRAM:sdram_init]: (0) SD_CS = 0x794200 0.242702 [SDRAM:sdram_init]: SDRAM Type: Elpida 1GB LPDDR2 (BC=0x58) 0.289496 [SDRAM:selftest]: Self test successful! 126.761881 [PLATFORM:platform_early_init]: 127.042734 [ARM:arm_init]: armid 0x364d5241, C0 0x0 127.172948 [ARM:bridgeStart]: starti...
by cleverca22
Tue Sep 21, 2021 4:43 am
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

download.png
download.png (10.06 KiB) Viewed 145 times
and once i figured out some alpha issues, i now have X11 working fully, complete with a login prompt and xeyes/xterm

xfce is building now...

this is what it looked like without fixing the alpha problems:
download (1).png
download (1).png (8.64 KiB) Viewed 145 times
by cleverca22
Tue Sep 21, 2021 1:22 am
Forum: General discussion
Topic: BCM2937 datasheet ??? RPi 3B+
Replies: 2
Views: 119

Re: BCM2937 datasheet ??? RPi 3B+

https://www.raspberrypi.org/documentati ... sion-codes

Code: Select all

[root@netboot-1:~]# grep Revision /proc/cpuinfo
Revision        : c03112
> (0xc03112 >> 12) & 0xf
3
this says that i'm on a bcm2711
by cleverca22
Mon Sep 20, 2021 3:21 pm
Forum: Bare metal, Assembly language
Topic: open firmware and booting custom apps fast
Replies: 51
Views: 2096

Re: open firmware and booting custom apps fast

ive now added a device-tree api between the main firmware and the arm bootloader that is then used to simplify configuring the linux framebuffer, and also pass along boot time metrics Screenshot_2021-09-20_12-10-01.png my efi laptop is reporting these numbers in "systemd-analyze plot" and ...
by cleverca22
Mon Sep 20, 2021 1:35 pm
Forum: General discussion
Topic: No more Rpi laptops?
Replies: 43
Views: 1268

Re: No more Rpi laptops?

there is the new framework laptop as well

it may be possible to make a CM4 based motherboard for it
by cleverca22
Mon Sep 20, 2021 7:21 am
Forum: Gaming
Topic: Seeking interest and support in a game designed for Rpi
Replies: 106
Views: 10445

Re: Seeking interest and support in a game designed for Rpi

several hundred thousand poly's at the moment i must be missing some feature or trick in the gpu, or the pi4 changed things, because i only see support for 16bit indexes into the vertex data so that means you have a hard limit of ~64k vertices, shared between all polygons anything more would requir...
by cleverca22
Sun Sep 19, 2021 11:18 pm
Forum: Device Tree
Topic: how to bind a clock source to cpufreq
Replies: 2
Views: 127

Re: how to bind a clock source to cpufreq

ah, so i should just need to somehow force cpufreq into loading, and then the clocks= and operating-points= should kick into gear?

but ive already built the kernel with cpufreq built in

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