linux-kernel - [PATCH 6.7 618/713] mei: gsc_proxy: match component when GSC is on different bus

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Date: Sun, 24 Mar 2024 18:45:44 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Alexander Usyskin <alexander.usyskin@...el.com>,
	Tomas Winkler <tomas.winkler@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 6.7 618/713] mei: gsc_proxy: match component when GSC is on different bus

From: Alexander Usyskin <alexander.usyskin@...el.com>

commit a0776c214d47ea4f7aaef138095beaa41cff03ef upstream.

On Arrow Lake S systems, MEI is no longer strictly connected to bus 0,
while graphics remain exclusively on bus 0. Adapt the component
matching logic to accommodate this change:

Original behavior: Required both MEI and graphics to be on the same
bus 0.

New behavior: Only enforces graphics to be on bus 0 (integrated),
allowing MEI to reside on any bus.
This ensures compatibility with Arrow Lake S and maintains functionality
for the legacy systems.

Fixes: 1dd924f6885b ("mei: gsc_proxy: add gsc proxy driver")
Cc: stable@...r.kernel.org # v6.3+
Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
Link: https://lore.kernel.org/r/20240220200020.231192-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c b/drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c
index be52b113aea93..89364bdbb1290 100644
--- a/drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c
+++ b/drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c
@@ -96,7 +96,8 @@ static const struct component_master_ops mei_component_master_ops = {
  *
  *    The function checks if the device is pci device and
  *    Intel VGA adapter, the subcomponent is SW Proxy
- *    and the parent of MEI PCI and the parent of VGA are the same PCH device.
+ *    and the VGA is on the bus 0 reserved for built-in devices
+ *    to reject discrete GFX.
  *
  * @dev: master device
  * @subcomponent: subcomponent to match (I915_COMPONENT_SWPROXY)
@@ -123,7 +124,8 @@ static int mei_gsc_proxy_component_match(struct device *dev, int subcomponent,
 	if (subcomponent != I915_COMPONENT_GSC_PROXY)
 		return 0;
 
-	return component_compare_dev(dev->parent, ((struct device *)data)->parent);
+	/* Only built-in GFX */
+	return (pdev->bus->number == 0);
 }
 
 static int mei_gsc_proxy_probe(struct mei_cl_device *cldev,
@@ -146,7 +148,7 @@ static int mei_gsc_proxy_probe(struct mei_cl_device *cldev,
 	}
 
 	component_match_add_typed(&cldev->dev, &master_match,
-				  mei_gsc_proxy_component_match, cldev->dev.parent);
+				  mei_gsc_proxy_component_match, NULL);
 	if (IS_ERR_OR_NULL(master_match)) {
 		ret = -ENOMEM;
 		goto err_exit;
-- 
2.43.0