From a80da7389891d0eeacbd568a9b54f665fd424d14 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Sat, 14 Jan 2006 13:21:23 -0800 Subject: [PATCH] gx1fb: (try to) play nicer with various BIOSes Seems that the CS5530A chip used in Geode GX1 systems has some crazy feature that causes SMI traps when accessing the PCI configuration space of the video device. Various GX1 BIOSes seem to use this 'feature' to hide the real BARs of the device. This patch disables these traps (in an early PCI fixup) so that Linux sees the real, physical BARs and not the virtual ones provided by the BIOS. This should allow the GX1 framebuffer driver to work on more systems that have different BIOSes as the driver no longer guesses at what the virtual BARs mean. I'm not entirely sure it the correct solution as I can neither test regular VGA console nor the X's 'cyrix' video driver so there might be some breakage there -- probably best to get some more testers before applying it. Signed-off-by: Antonino Daplas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/pci/fixup.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/i386/pci') diff --git a/arch/i386/pci/fixup.c b/arch/i386/pci/fixup.c index 65f67070db6..83c3645ccc4 100644 --- a/arch/i386/pci/fixup.c +++ b/arch/i386/pci/fixup.c @@ -449,3 +449,19 @@ static void __devinit pci_post_fixup_toshiba_ohci1394(struct pci_dev *dev) } DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_TI, 0x8032, pci_post_fixup_toshiba_ohci1394); + + +/* + * Prevent the BIOS trapping accesses to the Cyrix CS5530A video device + * configuration space. + */ +static void __devinit pci_early_fixup_cyrix_5530(struct pci_dev *dev) +{ + u8 r; + /* clear 'F4 Video Configuration Trap' bit */ + pci_read_config_byte(dev, 0x42, &r); + r &= 0xfd; + pci_write_config_byte(dev, 0x42, r); +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, + pci_early_fixup_cyrix_5530); -- cgit v1.2.3