Hello Robert, Andreas,
On 09-12-14 22:45, Robert Nelson wrote:
On Mon, Dec 8, 2014 at 4:19 PM, Jeroen Hofstee jeroen@myspectrum.nl wrote:
Hi,
A while ago [1], a RFC was posted to disable workaround for besides others, errata 430973. It is a bit unclear to me which revision actually need this workaround, but as suggested in [2] also enabling this workaround in Linux seem to make some weird problems go away in linux (signal 4, bad instruction, 11 segfaults etc).
As said, I am a bit in doubt why this works. The board in question is a tam3517 derived one:
cat /proc/cpuinfo Processor : ARMv7 Processor rev 7 (v7l) BogoMIPS : 397.57 Features : swp half thumb fastmult vfp edsp neon vfpv3 tls CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x1 CPU part : 0xc08 CPU revision : 7
Which makes this a r1p7 I assume, and hence the workaround of linux, CONFIG_ARM_ERRATA_430973, "This option enables the workaround for the 430973 Cortex-A8 (r1p0..r1p2) erratum", should not be needed it seems.
Digging thru my old beagle notes 430973 is also needed for "r1p3" (dm3730/bb-xm), so that config option was never updated since the errata was first discovered in r1p2 devices..
Fixed in r2p1 sounds about right, as i know for sure it works fine in 'r3p2' (am335x/bbb)
Thanks for the clarification. I sent a patch to the linux folks to update the help text.
Regards, Jeroen