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authorJiang Liu <jiang.liu@linux.intel.com>2014-02-20 17:23:16 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-02-20 21:19:47 +0100
commite284175a96e5af087ea7806b3e38282b524ff5b9 (patch)
treef5c085ac2ac29ecd34543394a4991d16895994d6 /drivers
parent6d0abeca3242a88cab8232e4acd7e2bf088f3bc2 (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.c26
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) {