Hi, > Phil Elwell <phil@xxxxxxxxxxxxxxx> hat am 12. September 2018 um 18:42 geschrieben: > > > Both sides of the VCHIQ communications mechanism need to agree on the cache > line size. Using an incorrect value can lead to data corruption, but having the > two sides using different values is usually worse. > > In the absence of an obvious convenient run-time method to determine the > correct value in the ARCH=arm world, the downstream Raspberry Pi trees used a > Device Tree property, written by the firmware, to configure the kernel driver. > This method was vetoed during the upstreaming process, so a fixed value of 32 > was used instead, and some corruptions ensued. This is take 2 at arriving at > the correct value. > > Part one of the fix is deriving the correct value from the ARM's cpuid register. > Part two is a (seemingly cosmetic) correction of the Device Tree reg declaration > used by the driver, but it doubles as an indication to the Raspberry Pi firmware > that the kernel driver is running a recent kernel driver that chooses the > correct value. As such I would like very much for the DT patch not to be merged > before the driver patch - just tell me what hoops I need to jump through. > even if this version isn't the best, the test results for vchiq_test -f 1 (using recent firmware 2018-09-10) are very good: Raspberry 1 B, bcm2835_defconfig -> success Raspberry 2 B, multi_v7_defconfig -> success Raspberry 3 B, arm64/defconfig -> success Thanks Stefan
