diff options
| author | Jiang Liu <jiang.liu@linux.intel.com> | 2014-02-20 17:23:16 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-02-20 21:19:47 +0100 |
| commit | e284175a96e5af087ea7806b3e38282b524ff5b9 (patch) | |
| tree | f5c085ac2ac29ecd34543394a4991d16895994d6 /drivers | |
| parent | 6d0abeca3242a88cab8232e4acd7e2bf088f3bc2 (diff) | |
ACPI / nouveau: fix probing regression related to _DSM
Fix regression caused by commit b072e53, which breaks loading nouveau
driver on optimus laptops.
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.
Fixes: b072e53b0a27 (ACPI / nouveau: replace open-coded _DSM code with helper functions)
Reported-and-tested-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
[rjw: Subject]
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/nouveau/nouveau_acpi.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index 4ef83df2b246..83face3f608f 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) { |