From a5ee4eb75413c145334c30e43f1af9875dad6fd7 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 22 Mar 2010 09:52:16 +0100 Subject: PCI quirk: RS780/RS880: work around missing MSI initialization AMD says in section 2.5.4 (GFX MSI Enable) of #43291 (AMD 780G Family Register Programming Requirements): The SBIOS must enable internal graphics MSI capability in GCCFG by setting the following: NBCFG.NB_CNTL.STRAP_MSI_ENABLE='1' Quite a few BIOS writers misinterpret this sentence and think that enabling MSI is an optional feature. However, clearing that bit just prevents delivery of MSI messages but does not remove the MSI PCI capabilities registers, and so leaves these devices unusable for any driver that attempts to use MSI. Setting that bit is not possible after the BIOS has locked down the configuration registers, so we have to manually disable MSI for the affected devices. This fixes the codec communication errors in the HDA driver when accessing the HDMI audio device, and allows us to get rid of the overcautious quirk in radeon_irq_kms.c. Signed-off-by: Clemens Ladisch Tested-by: Alex Deucher Cc: Signed-off-by: Jesse Barnes --- drivers/pci/quirks.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'drivers/pci') diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 8284958..bb5b46a 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -2493,6 +2493,39 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4374, DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4375, quirk_msi_intx_disable_bug); +/* + * MSI does not work with the AMD RS780/RS880 internal graphics and HDMI audio + * devices unless the BIOS has initialized the nb_cntl.strap_msi_enable bit. + */ +static void __init rs780_int_gfx_disable_msi(struct pci_dev *int_gfx_bridge) +{ + u32 nb_cntl; + + if (!int_gfx_bridge->subordinate) + return; + + pci_bus_write_config_dword(int_gfx_bridge->bus, PCI_DEVFN(0, 0), + 0x60, 0); + pci_bus_read_config_dword(int_gfx_bridge->bus, PCI_DEVFN(0, 0), + 0x64, &nb_cntl); + + if (!(nb_cntl & BIT(10))) { + dev_warn(&int_gfx_bridge->dev, + FW_WARN "RS780: MSI for internal graphics disabled\n"); + int_gfx_bridge->subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI; + } +} + +#define PCI_DEVICE_ID_AMD_RS780_P2P_INT_GFX 0x9602 + +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, + PCI_DEVICE_ID_AMD_RS780_P2P_INT_GFX, + rs780_int_gfx_disable_msi); +/* wrong vendor ID on M4A785TD motherboard: */ +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ASUSTEK, + PCI_DEVICE_ID_AMD_RS780_P2P_INT_GFX, + rs780_int_gfx_disable_msi); + #endif /* CONFIG_PCI_MSI */ #ifdef CONFIG_PCI_IOV -- cgit v1.1