From: Dave Jones At least one laptop blew up on resume from suspend with a black screen due to a lack of this patch. By only writing back config space that is different, we minimise the possibility of accidents like this. Signed-off-by: Dave Jones Cc: Greg KH Signed-off-by: Andrew Morton --- drivers/pci/pci.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff -puN drivers/pci/pci.c~improve-pci-config-space-writeback drivers/pci/pci.c --- devel/drivers/pci/pci.c~improve-pci-config-space-writeback 2006-04-18 21:06:15.000000000 -0700 +++ devel-akpm/drivers/pci/pci.c 2006-04-18 21:06:17.000000000 -0700 @@ -461,9 +461,19 @@ int pci_restore_state(struct pci_dev *dev) { int i; + int val; - for (i = 0; i < 16; i++) - pci_write_config_dword(dev,i * 4, dev->saved_config_space[i]); + for (i = 0; i < 16; i++) { + pci_read_config_dword(dev, i * 4, &val); + if (val != dev->saved_config_space[i]) { + printk(KERN_DEBUG "PM: Writing back config space on " + "device %s at offset %x (was %x, writing %x)\n", + pci_name(dev), i, + val, (int)dev->saved_config_space[i]); + pci_write_config_dword(dev,i * 4, + dev->saved_config_space[i]); + } + } pci_restore_msi_state(dev); pci_restore_msix_state(dev); return 0; _