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by Chris_G_Miller
Mon Jul 01, 2019 7:21 am
Forum: Troubleshooting
Topic: Pi becomes sluggish after a few hours, SD over-active - kiosk/chromium [Edited]
Replies: 2
Views: 471

Re: Pi becomes sluggish after a few hours, SD over-active - kiosk/chromium [Edited]

OK - I have finally worked it out. As my application has to run the SD card read-only, I have a small ramfs which I use for the user profile. The default user's home directory (/home/pi) is copied to the 100Mb ramfs on startup, and the home user has their home directory pointed to that location. I h...
by Chris_G_Miller
Sun Jun 30, 2019 9:21 am
Forum: Troubleshooting
Topic: Pi becomes sluggish after a few hours, SD over-active - kiosk/chromium [Edited]
Replies: 2
Views: 471

Re: Pi becomes sluggish after a few hours - kiosk/chromium [Edited]

Strangely, even after renaming the binary, it still seems able to run. Running iotop in logging mode (iotop -ob -d 10) from an SSH session, and logging the output, this process, spawned by chromium-browser, uses a small amount of disk read I/O from time to time In the snippet below, its average use ...
by Chris_G_Miller
Wed Jun 26, 2019 5:17 pm
Forum: Troubleshooting
Topic: Pi becomes sluggish after a few hours, SD over-active - kiosk/chromium [Edited]
Replies: 2
Views: 471

Pi becomes sluggish after a few hours, SD over-active - kiosk/chromium [Edited]

[Post heavily edited as original version contained misleading theories!] I am working on an R-Pi 3B based "kiosk" project. Even with just: lxde chromium-browser (version 72) displaying a static page node js the R-Pi was becoming unresponsive after a couple of hours running. The Green SD light was al...
by Chris_G_Miller
Wed Jun 26, 2019 7:14 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Can MIPI be used with non-official peripherals?
Replies: 11
Views: 3696

Re: Can MIPI be used with non-official peripherals?

I did eventually 'crack' getting the DSI to come on, and created a 'panel' driver for the TI chip you mention. The basic requirements are: - Switch off hardware detection of a display using ignore_lcd=1 and ignore_touchscreen=1 in /boot/config.txt - Create a Device Tree Overlay which adds the i2c po...
by Chris_G_Miller
Tue Jun 25, 2019 2:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: How can I remove unwanted display entity
Replies: 4
Views: 438

Re: How can I remove unwanted display entity

OK - the fact vec was running was an 'own goal' - I had accidentally enabled it in my dtb overlay. Having knocked that out, I get a 'clean' result from xrandr: [email protected]:/root $ xrandr Screen 0: minimum 320 x 200, current 480 x 800, maximum 2048 x 2048 DSI-1 connected primary 480x800+0+0 right ...
by Chris_G_Miller
Tue Jun 25, 2019 8:52 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: How can I remove unwanted display entity
Replies: 4
Views: 438

Re: How can I remove unwanted display entity

Thanks very much for that tip. I will try and 'knock out' the vec component, now I know that's what's doing it. Incidentally, is there any 'obvious' reference material I should be looking at so I could have discovered that easily? When I run arandr, I see the following if I hover over the Composite ...
by Chris_G_Miller
Tue Jun 25, 2019 7:39 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: How can I remove unwanted display entity
Replies: 4
Views: 438

How can I remove unwanted display entity

With Jesse, 4.19.46-v7+ and with just a DSI display connected, I am finding an unexpected entry when I run xrandr - 'Composite-1': I'm using the vc4-kms-v3d overlay with a portait mode LCD which is 800x480. output of xrandr: Screen 0: minimum 320 x 200, current 480 x 800, maximum 2048 x 2048 Composi...
by Chris_G_Miller
Wed Jun 19, 2019 3:20 pm
Forum: Beginners
Topic: Turning off composite RCA output
Replies: 5
Views: 753

Re: Turning off composite RCA output

I would also like to get rid of the entry Composite-1 in my setup - see for example output of xrandr: Screen 0: minimum 320 x 200, current 480 x 800, maximum 2048 x 2048 Composite-1 unknown connection primary (normal left inverted right x axis y axis) 720x480 62.69 DSI-1 connected 480x800+0+0 right ...
by Chris_G_Miller
Fri Jun 14, 2019 9:33 pm
Forum: General discussion
Topic: New Open GL Driver, Bug report thread
Replies: 98
Views: 45428

Re: New Open GL Driver, Bug report thread

I have a DSI-attached non-official display which works fine with vc4-kms-v3d when in normal landscape mode. However, if I switch to vc4-fkms-v3d I get no display at all. If I try to rotate the display using xrandr, occasionally it works, but more often than not the DSI signals stop, and therefore my...
by Chris_G_Miller
Thu Jun 06, 2019 10:14 pm
Forum: Device Tree
Topic: [SOLVED] Which dtb for which model?
Replies: 3
Views: 1267

Re: [SOLVED] Which dtb for which model?

Thank you for the clarification. I agree the parts of the filename like 'rpi-3-b' are really helpful, but how would one know whether bcm2710-rpi-3-b.dts or bcm2837-rpi-3-b.dts is the critical one for a Raspberry Pi 3 model B? I need to add clauses for the i2c_dsi interface under the soc. Those appea...
by Chris_G_Miller
Thu Dec 13, 2018 1:22 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

The word 'lane' is not the same as 'line' The 'lanes' are the data pairs. The two clock 'lines' operate differentially, so we are needing to pull them both up a little to meet the common mode range required by the Texas chip.
So it is correct that they are both pulled in the same direction.
by Chris_G_Miller
Thu Dec 13, 2018 11:35 am
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

I pulled them up to the Vcore pin on the interface chip (pin 31), as I think that is the internal supply for the DSI line receivers. It worked for me. As you say, it is unclear why this should be necessary, but it appears to be.
by Chris_G_Miller
Wed Dec 12, 2018 9:44 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

Just the clock lines, not the data lanes
by Chris_G_Miller
Wed Dec 12, 2018 6:02 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

Yes, it all works - but take note of my need to provide some DC bias on the DSI clock lines in my post (2k pullup on each wire) - did not have to mess with the Data lanes. I have now revised my design to use the I2C interface chip you managed to find, and it works a treat. I will shortly be re-visit...
by Chris_G_Miller
Fri Aug 03, 2018 7:35 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Can MIPI be used with non-official peripherals?
Replies: 11
Views: 3696

Re: Can MIPI be used with non-official peripherals?

For the time being, I've resorted to programming a cheap PIC to emulate the I2C transactions which the Pi firmware is expecting. It acts as an I2C slave, and gives the responses observed on the I2C bus from a 'real' panel. So now, if I allow the firmware to probe for an 'official' panel (i.e. do NOT...
by Chris_G_Miller
Mon Jul 30, 2018 8:02 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Can MIPI be used with non-official peripherals?
Replies: 11
Views: 3696

Re: Can MIPI be used with non-official peripherals?

I have managed to get the TI chip you mention working, but ONLY if I spoof the R-Pi into switching on the DSI port by hotwiring the I2C lines to a genuine R-Pi official 7" display. I found the DSI clock needed some pull-up resistors to get its DC level right for the TI chip to resolve the clock. But...
by Chris_G_Miller
Sat Jul 28, 2018 5:00 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

I am really struggling to get the Device Tree to make the R-Pi push out DSI signals to my DSI to LVDS bridge. The only way I've managed to do it so far is to hook up the I2C lines in parallel to an "official" display, which means the firmware detects the display, and lights up the DSI output. This i...
by Chris_G_Miller
Wed Jul 11, 2018 5:47 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

Re: DSI Device Tree Entries - module probe not being called

Yes - I have managed to make it work in that I can get a picture by kidding the R-Pi that it has an Official display attached. You may like to look at https://e2e.ti.com/support/interface/digital_interface/f/130/t/670554 where you'll see a little about my 'mission of discovery'! I have not yet crack...
by Chris_G_Miller
Wed Jun 27, 2018 11:19 pm
Forum: Device Tree
Topic: DSI Device Tree Entries - module probe not being called
Replies: 11
Views: 3542

DSI Device Tree Entries - module probe not being called

I am trying to get a DSI to LVDS bridge chip going. This can be directly setup using I2C - a situatiion very similar to the early drivers for the R-Pi Official 7" touch screen. However, with current Rasbian (4.14.50) if I connect an official screen, it works fine - but i cannot see any entries in th...
by Chris_G_Miller
Wed Jun 01, 2016 11:02 pm
Forum: Raspbian
Topic: Serial port missing - latest Jessie after update/upgrade
Replies: 8
Views: 24383

Re: Serial port missing - latest Jessie after update/upgrade

I was having terrible trouble with a serial peripheral attached via a USB to serial device, which I eventually tracked down to "odd" characters turning up in the serial stream my C program was sending to it. It turns out that Jessie (and possibly other distros) ships with something called ModemManag...
by Chris_G_Miller
Tue Apr 05, 2016 5:17 pm
Forum: Networking and servers
Topic: Pi2 gets static IP but also DHCP IP is assigned
Replies: 26
Views: 58735

Re: Pi2 gets static IP but also DHCP IP is assigned

I too fell slightly foul of dhcpcd (not to be confused with dhcpd - which I was, for several minutes) I too am doing "headless" stuff so need complete control over the IP addressing, and sometimes on networks where DHCP cannot be relied on to do this via reservations. And to make it even more confus...
by Chris_G_Miller
Mon Nov 16, 2015 3:14 pm
Forum: Troubleshooting
Topic: RPi 2 Ethernet Issues
Replies: 4
Views: 890

Re: RPi 2 Ethernet Issues

We too have had LAN ports die, including going unidirectional, and including Alan's "In addition, the status lights on the Ethernet port turn on and remain on whether a network cable is connected or not." In our case, we are using Power over Ethernet via our own design of HAT. It turns out that it i...

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