[Letux-kernel] Status LX16

[H. Nikolaus Schaller]

Hi Paul,

> Am 22.12.2024 um 23:04 schrieb Paul Boddie <paul at boddie.org.uk>:
> 
> On 2024-12-22 17:55, H. Nikolaus Schaller wrote:
>> If we finally find a fix for the SPI speed and DMA issues, it is IMHO mature enough to be
>> announced to some community (well, which one?) and start upstreaming of our patches.
> 
> What was the problem with SPI and DMA in the end? When I last checked, it seemed as if the SPI transfers were not being blocked, which had been a problem, but I suppose there might still have been problems with the DMA initialisation, necessitating a fallback on CPU-initiated transfers.
> 
> As for the speed, you probably saw my observations about the performance of the Waveshare board, which uses an unusual serial-to-parallel circuit to gain a few extra percent in performance. The controller is not really very fast, limiting the transfer clock to 20MHz, maybe 25MHz in some cases. This yields maybe ten frames per second at best.

Ah, I wasn't aware that you managed to get SPI speed up. On my setup I still run SPI with DMA disabled and at slow clock rate. And then get 1 fps max.

So this means I should simply give it a try?

> 
> [...]
> 
>> But everything is good enough now to build some units of version 0.4 early next year. And to
>> share some of them with you and Lumissil. And to start work on an LX20 prototype.
> 
> It sounds very promising. Further investigation with the 0.2 board will remain one of my priorities after the holidays. You may have seen this short article I wrote a couple of weeks ago:
> 
> https://blogs.fsfe.org/pboddie/?p=2910

Great and Thanks!

> 
>> So I wish everyone a Merry Christmas and a Happy New Year.
> 
> A Merry Christmas and Happy New Year to you and everyone else, too!

Again same to you,
Nikolaus