git: kernel - Adjust AHCI driver to deal with AMD braindamage / 880G chipset
dillon at crater.dragonflybsd.org
Thu Sep 16 19:56:28 PDT 2010
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Thu Sep 16 14:57:27 2010 -0700
kernel - Adjust AHCI driver to deal with AMD braindamage / 880G chipset
* As of this writing AMD has some new chipsets out for AM3 MBs which
supports AHCI on 5 SATA + 1 E-SATA connector. My testing was done
on a MB with the 880G chipset.
The AHCI firmware for this chipset is a bit on the rough side. It
seems a bit slow on the INIT/device-detection sequencing (possibly due
to longer PHY training time? It's supposed to be a 6GBit PHY), and it
generates a stream of PCS interrupts for some devices.
My assumption is that the PCS interrupts are not being masked by the
chipset during the INIT phase. Both IFS and PCS interrupts seem to
occur during INIT/RESET and PM probing stages.
In addition, at least one drive... an Intel SSD, caused a large number
of PCS interrupts during the INIT phase even when connected to an
internal SATA port at power-on. This is clearly a bug in the AMD
AHCI chipset, again related to their firmware not internally masking
communications glitches during INIT, and/or taking an extra long time
to train the PHY.
* Adjust the AHCI driver to deal with this situation. Limit the interrupt
rate for PCS errors and do harsh reinitialization of the port when we get
a PCS error, along with allowing extra time for the device detect to
* As a side benefit the AHCI driver should be able to deal with device
connection and disconnection on non-hot-swap-capable ports, at least
up to a point.
* Silence some of the console output during probe.
* Try harder to clear the CI/SACT registers when stopping a port. Some
chipsets appear to not clear the registers when we cycle ST when they
have already stopped the command processor, possibly as part of the IFS
or PCS interrupt paths.
* Fix a bug where an IFS or PCS interrupt marks a probe command (software
reset sequence) as complete when it actually errored-out.
* Sleep longer between retries if a command fails due to an IFS error.
When testing with the WD Green drives a drive inserted into a PM
enclosure cold seems to take longer to start up during the COMRESET
sequence. This only seems to occur with the AMD chipset and does
not occur with the older NVidia chipset. IFS errors occur for several
seconds beyond what I would consider a reasonable sleep interval.
Summary of changes:
sys/dev/disk/ahci/ahci.c | 351 ++++++++++++++++++++++++++++++++++---------
sys/dev/disk/ahci/ahci.h | 3 +-
sys/dev/disk/ahci/ahci_pm.c | 89 +++++++----
sys/dev/disk/ahci/atascsi.h | 2 +
4 files changed, 338 insertions(+), 107 deletions(-)
DragonFly BSD source repository
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