https://github.com/torvalds/linux
Revision dc9c41bd9ece090b54eb8f1bbdfb1930e10d3ae7 authored by Andrew Donnellan on 08 December 2015, 05:59:25 UTC, committed by Michael Ellerman on 09 December 2015, 03:05:10 UTC
This reverts commit 527d10ef3a315d3cb9dc098dacd61889a6c26439. The reverted commit breaks cxlflash devices following an EEH reset (and possibly other cxl devices, however this has not been tested). The reverted commit changed the behaviour of eeh_reset_device() so that PHB PEs are not unfrozen following the completion of the reset. This should not be problematic, as no device resources should have been associated with the PHB PE. However, when attempting to load the cxlflash driver after a reset, the driver attempts to read Vital Product Data through a call to pci_read_vpd() (which is called on the physical cxl device, not on the virtual AFU device). pci_read_vpd() in turn attempts to read from the cxl device's config space. This fails, as the PE it's trying to read from is still frozen. In turn, the driver gets an -ENODEV and fails to initialise. It appears this issue only affects some parts of the VPD area, as "lspci -vvv", which only reads a subset of the VPD bytes, is not broken by the original patch. At this stage, we don't fully understand why we're trying to read a frozen PE, and we don't know how this affects other cxl devices. It is possible that there is an underlying bug in the cxl driver or the powerpc CAPI support code, or alternatively a bug in the PCI resource allocation/mapping code that is incorrectly mapping resources to PE#0. As such, this fix is incomplete, however it is necessary to prevent a serious regression in CAPI support. In the meantime, revert the commit, especially as it was intended to be a non-functional change. Cc: Gavin Shan <gwshan@linux.vnet.ibm.com> Cc: Ian Munsie <imunsie@au1.ibm.com> Cc: Daniel Axtens <dja@axtens.net> Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 parent 5b01310
Tip revision: dc9c41bd9ece090b54eb8f1bbdfb1930e10d3ae7 authored by Andrew Donnellan on 08 December 2015, 05:59:25 UTC
Revert "powerpc/eeh: Don't unfreeze PHB PE after reset"
Revert "powerpc/eeh: Don't unfreeze PHB PE after reset"
Tip revision: dc9c41b
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arch | ||
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certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitignore | -rw-r--r-- | 1.2 KB |
.mailmap | -rw-r--r-- | 5.4 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 94.9 KB |
Kbuild | -rw-r--r-- | 2.6 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 328.3 KB |
Makefile | -rw-r--r-- | 53.5 KB |
README | -rw-r--r-- | 18.2 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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