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PiSupply / PaPiRus

Resources for PaPiRus ePaper eInk displays
https://www.pi-supply.com/product/papirus-epaper-eink-screen-hat-for-raspberry-pi/
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Has this been tested on the latest 5.4 kernels? #215

Closed pelwell closed 3 years ago

pelwell commented 3 years ago

Hi,

We've noticed that a number of displays have stopped working with the switch to the 5.4 kernel. This is caused by a change to the use of GPIO descriptors by some of the display drivers (mainly fbtft, but their might be others). Have you tested the PaPiRus displays on rpi-5.4.y? If you haven't and you find that it doesn't work, try changing the reset-gpios property in the overlay to reset-gpios = <&gpio 24 1>;.

shawaj commented 3 years ago

@ChristopherRush or @ryanteck could you give this a try?

ryanteck commented 3 years ago

Will do shortly,

IRC we don't use fbtft so it shouldn't be affected.

ChristopherRush commented 3 years ago

Will boot one up now

ryanteck commented 3 years ago

@ChristopherRush Ok then I'll leave it.

shawaj commented 3 years ago

The only thing that uses framebuffer is the fbcopy script https://github.com/PiSupply/PaPiRus/blob/master/bin/papirus-fbcopy

Other than that it's the EPD fuse stuff in rePaper/gratis repo

pelwell commented 3 years ago

I took a brief look at the repaper driver after posting and I think it's OK - unlike fbtft, the knowledge that reset is active-low seems to be built into the code, not learnt from Device Tree.

shawaj commented 3 years ago

@pelwell thanks very much for the heads up!

shawaj commented 3 years ago

@ChristopherRush if you have time can you test the media center hat as well?

ChristopherRush commented 3 years ago

@shawaj Yes will do

shawaj commented 3 years ago

See Ryan's comments here too https://github.com/PiSupply/Media-Center-HAT/issues/11#issuecomment-702691898

ChristopherRush commented 3 years ago

@pelwell How did you test the display?

pelwell commented 3 years ago

I didn't - I asked the question because a number of other displays have had problems under 5.4.

I've already speculatively fixed the Media Center overlay - see https://github.com/raspberrypi/linux/commit/b7d685c0b1bd1b98af0e9c1f5d43769982bdbfb2#diff-dc041e47200262dfab1ff9f9e0ef64c7

ChristopherRush commented 3 years ago

@shawaj @pelwell @ryanteck So far it is working fine. I'm using a Pi 4 with the PaPiRus HAT and 2.7" display. Kernel version is 5.4.51 and I have tested the following: papirus-clear papirus-clock papirus-fbcopy papirus-snake

pelwell commented 3 years ago

If it was affected then it would have been dead-on-arrival - this isn't a subtle bug.

shawaj commented 3 years ago

@pelwell guessing for hard-coded eeprom based dt blobs they'll need to override etc the new overlay in config.txt ?

Will make sure new batch uses new overlay

tvoverbeek commented 3 years ago

Did a quick test on a Pi 2B with the 2.0 inch screen (200x96) kernel 5.4.51. papirus-test, papirus-fbcopy, papirus-clock all work fine.

pelwell commented 3 years ago

Unfortunately yes - if the EEPROM includes the overlay content then you are going to need to apply the overlay. I now recommend putting the name of the overlay in the EEPROM rather than the .dtbo itself - the firmware will load the current version.

shawaj commented 3 years ago

@pelwell ah perfect, so does that just go in the settings.txt? Or elsewhere?

pelwell commented 3 years ago

That would have been nice, wouldn't it, but no. Instead, you put the name of the overlay - in this case "papirus" - in a .txt file and use that in place of papirus.dtbo:

$ echo papirus > myoverlay_name.txt
$ eepmake mysettings.txt myhat.eep myoverlay_name.txt

Any trailing whitespace is stripped, so don't worry about newlines etc.

This is covered in the current version of https://github.com/raspberrypi/hats/blob/master/devicetree-guide.md.

shawaj commented 3 years ago

@pelwell does the name of the .txt file have to be the same as the overlay too? Or just the contents?

i.e. should is be called papirus.txt as well or can it be anything?

pelwell commented 3 years ago

Anything you like - it's just a source of the bytes that get merged.

shawaj commented 3 years ago

@pelwell awesome, thanks very much that's very useful to know. Have a great weekend :-)

tvoverbeek commented 3 years ago

@pelwell Phil, Your changes to the media-center-overlay.dts work. Without them (using the original overlay) I get a black screen without backlight on. When can we expect them in apt update?

pelwell commented 3 years ago

I don't have a date at the moment, but the SPI CS changes give us a reason to push one or two more 5.4 kernels into apt before switching to 5.9/5.10.

pelwell commented 3 years ago

The latest rpi-update firmware has also been pushed to the "stable" branch (sudo BRANCH=stable rpi-update). If no problems are reported overnight it we'll probably bump the apt packages tomorrow.

tvoverbeek commented 3 years ago

Thanks Phil. WIll keep an eye on apt update

pelwell commented 3 years ago

The update should be live round-about now.

tvoverbeek commented 3 years ago

Thanks. Latest apt update (22 Oct) has the corrcted media-overlay