linux-kernel - [PATCH 3.16 132/346] drm/nouveau/acpi: return supported DSM functions

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Message-ID: <lsq.1479082460.880982462@decadent.org.uk>
Date:   Mon, 14 Nov 2016 00:14:20 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Hans de Goede" <hdegoede@...hat.com>,
        "Peter Wu" <peter@...ensteyn.nl>, Dave@...adent.org.uk,
        "Ben Skeggs" <bskeggs@...hat.com>
Subject: [PATCH 3.16 132/346] drm/nouveau/acpi: return supported DSM functions

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Wu <peter@...ensteyn.nl>

commit a12e78dd3e727094e449ee4e3b752ea9b6f8db01 upstream.

Return the set of supported functions to the caller. No functional
changes.

Reviewed-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Peter Wu <peter@...ensteyn.nl>
Acked-by: Dave Airlie <airlied@...hat.com
Signed-off-by: Ben Skeggs <bskeggs@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpu/drm/nouveau/nouveau_acpi.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -108,7 +108,7 @@ static int nouveau_optimus_dsm(acpi_hand
  * requirements on the fourth parameter, so a private implementation
  * instead of using acpi_check_dsm().
  */
-static int nouveau_check_optimus_dsm(acpi_handle handle)
+static int nouveau_dsm_get_optimus_functions(acpi_handle handle)
 {
 	int result;
 
@@ -123,7 +123,9 @@ static int nouveau_check_optimus_dsm(acp
 	 * 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);
+	if (result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS))
+		return result;
+	return 0;
 }
 
 static int nouveau_dsm(acpi_handle handle, int func, int arg)
@@ -215,7 +217,7 @@ static void nouveau_dsm_pci_probe(struct
 {
 	acpi_handle dhandle;
 	bool supports_mux;
-	bool supports_opt;
+	int optimus_funcs;
 
 	dhandle = ACPI_HANDLE(&pdev->dev);
 	if (!dhandle)
@@ -227,17 +229,17 @@ static void nouveau_dsm_pci_probe(struct
 	}
 	supports_mux = acpi_check_dsm(dhandle, nouveau_dsm_muid, 0x00000102,
 				      1 << NOUVEAU_DSM_POWER);
-	supports_opt = nouveau_check_optimus_dsm(dhandle);
+	optimus_funcs = nouveau_dsm_get_optimus_functions(dhandle);
 
 	/* Does not look like a Nvidia device. */
-	if (!supports_mux && !supports_opt)
+	if (!supports_mux && !optimus_funcs)
 		return;
 
 	*dhandle_out = dhandle;
 	*has_mux = supports_mux;
-	*has_opt = supports_opt;
+	*has_opt = !!optimus_funcs;
 
-	if (supports_opt) {
+	if (optimus_funcs) {
 		uint32_t result;
 		nouveau_optimus_dsm(dhandle, NOUVEAU_DSM_OPTIMUS_CAPS, 0,
 				    &result);