drm/amdgpu: Disable PCIe dynamic speed switching on Ryzen Pinnacle Ridge

commit 0148ac3 upstream.

AMD Ryzen Pinnacle Ridge (Zen+, family 0x17 model 0x08) CPUs have
PCI controllers that don't support PCIe dynamic speed switching,
causing system freezes during GPU initialization when enabled.

Disable dynamic speed switching when this CPU is detected.

Assisted-by: Claude:sonnet
Fixes: 466a7d1 ("drm/amd: Use the first non-dGPU PCI device for BW limits")
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5436
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Link: https://patch.msgid.link/20260709031520.841611-1-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 9ceb4e0)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: superm1

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -1757,6 +1757,15 @@ static bool amdgpu_device_pcie_dynamic_switching_supported(struct amdgpu_device
 
 	if (c->x86_vendor == X86_VENDOR_INTEL)
 		return false;
+
+	/*
+	 * AMD Ryzen Pinnacle Ridge (Zen+, family 0x17 model 0x08) CPUs don't
+	 * support PCIe dynamic speed switching.
+	 * https://gitlab.freedesktop.org/drm/amd/-/work_items/5436
+	 */
+	if (c->x86_vendor == X86_VENDOR_AMD && c->x86 == 0x17 &&
+	    c->x86_model == 0x08)
+		return false;
 #endif
 	return true;
 }