On Wed, Jun 19, 2019 at 05:17:59PM +0300, Jarkko Nikula wrote: > Hi > > On 6/19/19 4:58 PM, Ard Biesheuvel wrote: > > So can you explain how exactly the I2C GPIO expander is failing? I > > struggle to understand how the SPI slave probing could be related to > > that. > > > They don't show up in /sys/kernel/debug/gpio, are not present in > /sys/bus/i2c/devices/ but SPI core instead tries add them with a bogus Chip > Select number: > > [ 5.727699][ T1] pxa2xx-spi pxa2xx-spi.5: cs56 >= max 4 > [ 5.733545][ T1] spi_master spi5: failed to add SPI device INT3491:00 > from ACPI Just a guess but looking at the 4c3c59544f33 acpi_register_spi_device() does not seem to zero fill the whole struct acpi_spi_lookup structure so when it is supposed to bail out when SPI slave was not found: if (!lookup.max_speed_hz) return AE_OK it instead continues to register SPI slave because lookup.max_speed_hz may contain whatever garbage there is in the stack at that address.
