"Guilherme G. Piccoli" <gpicc...@linux.vnet.ibm.com> writes:
> During a kdump kernel boot in PowerPC, we request a reset of the > PHBs to the FW. It makes sense, since if we are booting a kdump > kernel it means we had some trouble before and we cannot rely in > the adapters' health; they could be in a bad state, hence the > reset is needed. > > But not only in a kdump kernel we could use this reset - there are > situations, specially when debugging drivers, that we could break > an adapter in a way it requires such reset. One can tell to just > go ahead and reboot the machine, but happens that many times doing > kexec is much faster, and so preferable than a full power cycle. > Also, we could have situations in which adapters are in bad state > due to adapter's FW issue, and only a PHB Fundamental Reset could > revive them. > > This patch enables the reset_devices parameter to perform such reset. > The parameter is barely used - only few drivers make use of it. > This is a PowerPC-only change. > > Signed-off-by: Guilherme G. Piccoli <gpicc...@linux.vnet.ibm.com> > --- > This patch was built/tested against powerpc/next branch. > > We recently had a situation in which i40e driver couldn't start, > even after a full power cycle, due to a bug in its FW triggered > by a DCB condition in switch (thanks Mauro for narrowing this). > This patch enabled us to revive the adapter and use network > while debugging. I really dislike this. You're basically saying the kernel can't work out how to get a device working, so let's leave it up to the user. The driver should be fixed to detect that the device is not responding and request a reset. cheers
