ChangeSet 1.1717.6.26, 2004/05/26 15:37:25-07:00, arjanv@redhat.com [PATCH] PCI: restore pci config space on resume The patch below enhances the PCI layer with 2 things 1) enable and busmaster state are stored in the pci device struct 2) pci config space is stored to the pci device struct with that, it is possible to make a generic pci resume method that restores config space and reenables the device, including busmaster when appropriate. One can rightfully argue that the driver resume method should do this, and yes that is right. So the patch only does it for devices that don't have a resume method. Like the main PCI bridge on my testbox of which the bios so nicely forgets to restore the bus master bit during resume.. With this patch my testbox resumes just fine while it, well, wasn't all too happy as you can imagine without a busmaster pci bridge. drivers/pci/pci-driver.c | 26 ++++++++++++++++++++++++-- drivers/pci/pci.c | 5 +++++ include/linux/pci.h | 5 +++++ 3 files changed, 34 insertions(+), 2 deletions(-) diff -Nru a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c --- a/drivers/pci/pci-driver.c Fri May 28 14:29:10 2004 +++ b/drivers/pci/pci-driver.c Fri May 28 14:29:10 2004 @@ -299,10 +299,30 @@ { struct pci_dev * pci_dev = to_pci_dev(dev); struct pci_driver * drv = pci_dev->driver; + int i = 0; if (drv && drv->suspend) - return drv->suspend(pci_dev,state); - return 0; + i = drv->suspend(pci_dev,state); + + pci_save_state(pci_dev, pci_dev->saved_config_space); + return i; +} + + +/* + * Default resume method for devices that have no driver provided resume, + * or not even a driver at all. + */ +static void pci_default_resume(struct pci_dev *pci_dev) +{ + /* restore the PCI config space */ + pci_restore_state(pci_dev, pci_dev->saved_config_space); + /* if the device was enabled before suspend, reenable */ + if (pci_dev->is_enabled) + pci_enable_device(pci_dev); + /* if the device was busmaster before the suspend, make it busmaster again */ + if (pci_dev->is_busmaster) + pci_set_master(pci_dev); } static int pci_device_resume(struct device * dev) @@ -312,6 +332,8 @@ if (drv && drv->resume) drv->resume(pci_dev); + else + pci_default_resume(pci_dev); return 0; } diff -Nru a/drivers/pci/pci.c b/drivers/pci/pci.c --- a/drivers/pci/pci.c Fri May 28 14:29:10 2004 +++ b/drivers/pci/pci.c Fri May 28 14:29:10 2004 @@ -385,6 +385,7 @@ int pci_enable_device(struct pci_dev *dev) { + dev->is_enabled = 1; return pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1); } @@ -399,6 +400,9 @@ pci_disable_device(struct pci_dev *dev) { u16 pci_command; + + dev->is_enabled = 0; + dev->is_busmaster = 0; pci_read_config_word(dev, PCI_COMMAND, &pci_command); if (pci_command & PCI_COMMAND_MASTER) { @@ -601,6 +605,7 @@ cmd |= PCI_COMMAND_MASTER; pci_write_config_word(dev, PCI_COMMAND, cmd); } + dev->is_busmaster = 1; pcibios_set_master(dev); } diff -Nru a/include/linux/pci.h b/include/linux/pci.h --- a/include/linux/pci.h Fri May 28 14:29:10 2004 +++ b/include/linux/pci.h Fri May 28 14:29:10 2004 @@ -488,6 +488,11 @@ /* These fields are used by common fixups */ unsigned int transparent:1; /* Transparent PCI bridge */ unsigned int multifunction:1;/* Part of multi-function device */ + /* keep track of device state */ + unsigned int is_enabled:1; /* pci_enable_device has been called */ + unsigned int is_busmaster:1; /* device is busmaster */ + + unsigned int saved_config_space[16]; /* config space saved at suspend time */ #ifdef CONFIG_PCI_NAMES #define PCI_NAME_SIZE 96 #define PCI_NAME_HALF __stringify(43) /* less than half to handle slop */