** Tags added: raspi-image

** Package changed: ubuntu => linux (Ubuntu)

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https://bugs.launchpad.net/bugs/1926801

Title:
   BCM2835 SPI chipselect limit - kernel/driver panic

Status in linux package in Ubuntu:
  New

Bug description:
  Bug fix was just committed by Phil Elwell <p...@raspberrypi.com>, and
  appears as response driver error reported for Raspberry Pi OS. I have
  the same problem with driver in Ubuntu 21.04. My apology for not
  knowing how driver fixes are coordinated across Pi OS and Ubuntu, so I
  am providing the information here in hopes a fix will be made
  available in Ubuntu 21.04. Please let me know if driver fix will be
  available for 21.04.

  As background, my previous comment on github in discussion of problem with 
Mr. Elwell was:
  A limit of 24 chipselects would work for me. -- This would likely solve 
problem seeing a kernel panic (bad kernel memory reference) in 
5.11.0-1007-raspi after configuring 6 chipselects for for BCM2835 SPI via 
dtoverlay. Kernel panic is on shutdown/reboot, however, memory corruption for 
more than 4 chipselects likely has other runtime consequences.

  -------
  Details on new driver commit for drivers/spi/spi-bcm2835.c from Mr. Elwell on 
4-30-2021:

  
https://github.com/raspberrypi/linux/commit/05f8d5826e28e9d82485c03b65c18d5013ba13bd

  spi: bcm2835: Increase the CS limit to 24

  Increase the maximum number of CS lines to 24, and ensure this limit is
  not exceeded.

  See: #4281 -- https://github.com/raspberrypi/linux/pull/4281

  Suggested-by: Joe Burmeister <joe.burmeis...@devtank.co.uk>
  Signed-off-by: Phil Elwell <p...@raspberrypi.com>

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