On Mon, Mar 22, 2010 at 4:52 AM, Clemens Ladisch <clemens@xxxxxxxxxx> wrote:
> 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.
Looks good. This works properly on my rs780.
Tested-by: Alex Deucher <alexdeucher@xxxxxxxxx>
>
> Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxx>
> ---
> drivers/pci/quirks.c | 31 +++++++++++++++++++++++++++++++
> drivers/gpu/drm/radeon/radeon_irq_kms.c | 8 +-------
> 2 files changed, 32 insertions(+), 7 deletions(-)
>
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2479,6 +2479,39 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AT
> 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
> --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
> +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
> @@ -116,13 +116,7 @@ int radeon_irq_kms_init(struct radeon_de
> }
> /* enable msi */
> rdev->msi_enabled = 0;
> - /* MSIs don't seem to work on my rs780;
> - * not sure about rs880 or other rs780s.
> - * Needs more investigation.
> - */
> - if ((rdev->family >= CHIP_RV380) &&
> - (rdev->family != CHIP_RS780) &&
> - (rdev->family != CHIP_RS880)) {
> + if (rdev->family >= CHIP_RV380) {
> int ret = pci_enable_msi(rdev->pdev);
> if (!ret) {
> rdev->msi_enabled = 1;
>
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