Re: [net-next 6/6] can: mcp251xfd: mcp251xfd_regmap_crc_read(): work around broken CRC on TBC register

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 4/21/21 9:58 PM, Drew Fustini wrote:
> I am encountering similar error with the 5.10 raspberrypi kernel on
> RPi 4 with MCP2518FD:
> 
>   mcp251xfd spi0.0 can0: CRC read error at address 0x0010 (length=4,
> data=00 ad 58 67, CRC=0xbbfd) retrying

What's the situation you see these errors?

I'm not particular happy with that patch, as it only works around that one
particular bit flip issue. If you really hammer the register, the driver will
still notice CRC errors that can be explained by other bits flipping. Consider
this as the first order approximation of a higher order problem :) - the root
cause is still unknown.

> Would it be possible for you to pull these patches into a v5.10 branch
> in your linux-rpi repo [1]?

Here you are:

https://github.com/marckleinebudde/linux-rpi/tree/v5.10-rpi/backport-performance-improvements

I've included the UINC performance enhancements, too. The branch is compiled
tested only, though. I'll send a pull request to the rpi kernel after I've
testing feedback from you.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |


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