[PATCH v2] drm/i915/cx0_phy: Fix ARL-S host bridge detection

[Dnyaneshwar Bhadane <dnyaneshwar.bhadane@intel.com>]

Fix is_arrowlake_s_by_host_bridge() which always returned false.
The while loop always exits with pdev as NULL, so the return
condition was always false, causing the wrong tx_misc value to be used.

Check the host bridge ID inside the loop body.  Once found early exit
from the loop release the pci reference "pdev" and return true.

v2:
 - Update commit message (Chaitanya)

Bspec:74165,74491
Suggested-by: Jani Nikula <jani.nikula@intel.com>
Cc: <stable@vger.kernel.org>
Fixes: 3630a47b700e ("drm/i915/cx0_phy: Update HDMI TMDS C20 algorithm value")
Signed-off-by: Dnyaneshwar Bhadane <dnyaneshwar.bhadane@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index dbebd7210848..de450ebf541f 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -2342,12 +2342,14 @@ static void intel_c10pll_dump_hw_state(struct drm_printer *p,
 static bool is_arrowlake_s_by_host_bridge(void)
 {
 	struct pci_dev *pdev = NULL;
-	u16 host_bridge_pci_dev_id;
-
-	while ((pdev = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, pdev)))
-		host_bridge_pci_dev_id = pdev->device;
+	while ((pdev = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, pdev))) {
+		if (IS_ARROWLAKE_S_BY_HOST_BRIDGE_ID(pdev->device)) {
+			pci_dev_put(pdev);
+			return true;
+		}
+	}
 
-	return pdev && IS_ARROWLAKE_S_BY_HOST_BRIDGE_ID(host_bridge_pci_dev_id);
+	return false;
 }
 
 static u16 intel_c20_hdmi_tmds_tx_cgf_1(struct intel_display *display)
-- 
2.54.0