From: Bjorn Helgaas Date: Tue, 21 May 2013 16:56:51 +0000 (-0600) Subject: PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~18^2~11^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2add0ec14c259471d45d6afd051ca02eef0a4a92;p=pandora-kernel.git PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it Some devices have hardware problems related to using ASPM. Drivers for these devices use pci_disable_link_state() to prevent their device from entering L0s or L1. But on platforms where the OS doesn't have permission to manage ASPM, pci_disable_link_state() doesn't actually disable ASPM. Windows has a similar mechanism ("PciASPMOptOut"), and when the OS doesn't have control of ASPM, it doesn't actually disable ASPM either. This patch just adds a warning in dmesg about the fact that pci_disable_link_state() is doing nothing. Reported-by: Emmanuel Grumbach Reference: https://lkml.kernel.org/r/CANUX_P3F5YhbZX3WGU-j1AGpbXb_T9Bis2ErhvKkFMtDvzatVQ@mail.gmail.com Reference: https://bugzilla.kernel.org/show_bug.cgi?id=57331 Signed-off-by: Bjorn Helgaas --- Reading git-diff-tree failed