[PATCH] nouveau, ACPI: fix regression caused by b072e53 (original) (raw)

Jiang Liu jiang.liu at linux.intel.com
Tue Feb 18 20:53:43 PST 2014

On some platforms, ACPI _DSM method (nouveau_op_dsm_muid, function 0) has special requirements on the fourth parameter, which is different from ACPI specifications. So revert to the private implementation to check availability of _DSM functions instead of using common acpi_check_dsm() interface.

Signed-off-by: Jiang Liu <jiang.liu at linux.intel.com>

Hi Maarten, Thanks for bisecting. Could you please help to verify whether this patch fixes the regression?

Thanks! Gerry

drivers/gpu/drm/nouveau/nouveau_acpi.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index 4ef83df..c6c7d0d 100644 --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c @@ -106,6 +106,29 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t * return 0; } +/* + * On some platforms, _DSM(nouveau_op_dsm_muid, func0) has special + * requirements on the fourth parameter, so a private implementation + * instead of using acpi_check_dsm(). + / +static int nouveau_check_optimus_dsm(acpi_handle handle) +{ + int result; + + / + * Function 0 returns a Buffer containing available functions. + * The args parameter is ignored for function 0, so just put 0 in it + / + if (nouveau_optimus_dsm(handle, 0, 0, &result) + return 0; + + / + * ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported. + * If the n-th bit is enabled, function n is supported + */ + return result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS); +} + static int nouveau_dsm(acpi_handle handle, int func, int arg) { int ret = 0; @@ -207,8 +230,7 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev) 1 << NOUVEAU_DSM_POWER)) retval |= NOUVEAU_DSM_HAS_MUX; - if (acpi_check_dsm(dhandle, nouveau_op_dsm_muid, 0x00000100, - 1 << NOUVEAU_DSM_OPTIMUS_CAPS)) + if (nouveau_check_optimus_dsm(dhandle)) retval |= NOUVEAU_DSM_HAS_OPT; if (retval & NOUVEAU_DSM_HAS_OPT) {

1.7.10.4

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