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* [PATCH] drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans()
@ 2025-10-02  0:56 mallesh.koujalagi
  2025-10-02  1:03 ` ✓ CI.KUnit: success for drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans() (rev3) Patchwork
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: mallesh.koujalagi @ 2025-10-02  0:56 UTC (permalink / raw)
  To: intel-xe, rodrigo.vivi, lucas.demarchi
  Cc: anshuman.gupta, badal.nilawar, riana.tauro, karthik.poosa,
	sk.anirban, raag.jadav, Mallesh Koujalagi

From: Mallesh Koujalagi <mallesh.koujalagi@intel.com>

Initialize the uval variable to 0 in xe_late_bind_fw_num_fans() to fix
a potential use of uninitialized variable warning and ensure predictable
behavior.

The variable is passed by reference to xe_pcode_read() which should
populate it on success, but initializing it to 0 provides a safe
default value and follows kernel coding best practices.

v2:
- uval = 0 which serves as both a safe default and the fallback
  value when the pcode read operation fails.

v3:
- Handle MMIO failure (Rodrigo)
- The function should probably return the error and make the uval as
  pointer-argument, like the pcode_read.
- Change the caller of this function to propagate the error
  upwards if mmio failed.

Fixes: 45832bf9c10f3 ("drm/xe/xe_late_bind_fw: Initialize late binding firmware")
Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
---
 drivers/gpu/drm/xe/xe_late_bind_fw.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_late_bind_fw.c b/drivers/gpu/drm/xe/xe_late_bind_fw.c
index 8f5082e689dc..768442ca7da6 100644
--- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
+++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
@@ -184,17 +184,13 @@ static const char *xe_late_bind_parse_status(uint32_t status)
 	}
 }
 
-static int xe_late_bind_fw_num_fans(struct xe_late_bind *late_bind)
+static int xe_late_bind_fw_num_fans(struct xe_late_bind *late_bind, u32 *num_fans)
 {
 	struct xe_device *xe = late_bind_to_xe(late_bind);
 	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
-	u32 uval;
 
-	if (!xe_pcode_read(root_tile,
-			   PCODE_MBOX(FAN_SPEED_CONTROL, FSC_READ_NUM_FANS, 0), &uval, NULL))
-		return uval;
-	else
-		return 0;
+	return xe_pcode_read(root_tile,
+			     PCODE_MBOX(FAN_SPEED_CONTROL, FSC_READ_NUM_FANS, 0), num_fans, NULL);
 }
 
 void xe_late_bind_wait_for_worker_completion(struct xe_late_bind *late_bind)
@@ -314,7 +310,11 @@ static int __xe_late_bind_fw_init(struct xe_late_bind *late_bind, u32 fw_id)
 	lb_fw->flags &= ~INTEL_LB_FLAG_IS_PERSISTENT;
 
 	if (lb_fw->type == INTEL_LB_TYPE_FAN_CONTROL) {
-		num_fans = xe_late_bind_fw_num_fans(late_bind);
+		ret = xe_late_bind_fw_num_fans(late_bind, &num_fans);
+		if (ret) {
+			drm_dbg(&xe->drm, "Failed to read number of fans: %d\n", ret);
+			return 0; /* Not a fatal error, continue without fan control */
+		}
 		drm_dbg(&xe->drm, "Number of Fans: %d\n", num_fans);
 		if (!num_fans)
 			return 0;
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans()
@ 2025-10-01  1:09 mallesh.koujalagi
  2025-10-01 15:29 ` Rodrigo Vivi
  0 siblings, 1 reply; 10+ messages in thread
From: mallesh.koujalagi @ 2025-10-01  1:09 UTC (permalink / raw)
  To: intel-xe, rodrigo.vivi, lucas.demarchi
  Cc: anshuman.gupta, badal.nilawar, riana.tauro, karthik.poosa,
	sk.anirban, raag.jadav, Mallesh Koujalagi

From: Mallesh Koujalagi <mallesh.koujalagi@intel.com>

Initialize the uval variable to 0 in xe_late_bind_fw_num_fans() to fix
a potential use of uninitialized variable warning and ensure predictable
behavior.

The variable is passed by reference to xe_pcode_read() which should
populate it on success, but initializing it to 0 provides a safe
default value and follows kernel coding best practices.

v2:
- uval = 0 which serves as both a safe default and the fallback
  value when the pcode read operation fails.

Fixes: 45832bf9c10f3 ("drm/xe/xe_late_bind_fw: Initialize late binding firmware")
Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
---
 drivers/gpu/drm/xe/xe_late_bind_fw.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_late_bind_fw.c b/drivers/gpu/drm/xe/xe_late_bind_fw.c
index 38f3feb2aecd..46981a6f28ae 100644
--- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
+++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
@@ -188,13 +188,11 @@ static int xe_late_bind_fw_num_fans(struct xe_late_bind *late_bind)
 {
 	struct xe_device *xe = late_bind_to_xe(late_bind);
 	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
-	u32 uval;
+	u32 uval = 0;
 
-	if (!xe_pcode_read(root_tile,
-			   PCODE_MBOX(FAN_SPEED_CONTROL, FSC_READ_NUM_FANS, 0), &uval, NULL))
-		return uval;
-	else
-		return 0;
+	xe_pcode_read(root_tile,
+		      PCODE_MBOX(FAN_SPEED_CONTROL, FSC_READ_NUM_FANS, 0), &uval, NULL);
+	return uval;
 }
 
 void xe_late_bind_wait_for_worker_completion(struct xe_late_bind *late_bind)
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans()
@ 2025-10-01  0:53 mallesh.koujalagi
  0 siblings, 0 replies; 10+ messages in thread
From: mallesh.koujalagi @ 2025-10-01  0:53 UTC (permalink / raw)
  To: intel-xe, rodrigo.vivi, lucas.demarchi
  Cc: anshuman.gupta, badal.nilawar, riana.tauro, karthik.poosa,
	sk.anirban, raag.jadav, Mallesh Koujalagi

From: Mallesh Koujalagi <mallesh.koujalagi@intel.com>

Initialize the uval variable to 0 in xe_late_bind_fw_num_fans() to fix
a potential use of uninitialized variable warning and ensure predictable
behavior.

The variable is passed by reference to xe_pcode_read() which should
populate it on success, but initializing it to 0 provides a safe
default value and follows kernel coding best practices.

Fixes: 45832bf9c10f3 ("drm/xe/xe_late_bind_fw: Initialize late binding firmware")
Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
---
 drivers/gpu/drm/xe/xe_late_bind_fw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_late_bind_fw.c b/drivers/gpu/drm/xe/xe_late_bind_fw.c
index 38f3feb2aecd..a86d7fa611e2 100644
--- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
+++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
@@ -188,7 +188,7 @@ static int xe_late_bind_fw_num_fans(struct xe_late_bind *late_bind)
 {
 	struct xe_device *xe = late_bind_to_xe(late_bind);
 	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
-	u32 uval;
+	u32 uval = 0;
 
 	if (!xe_pcode_read(root_tile,
 			   PCODE_MBOX(FAN_SPEED_CONTROL, FSC_READ_NUM_FANS, 0), &uval, NULL))
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2025-10-03 14:21 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2025-10-02  0:56 [PATCH] drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans() mallesh.koujalagi
2025-10-02  1:03 ` ✓ CI.KUnit: success for drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans() (rev3) Patchwork
2025-10-02  1:44 ` ✓ Xe.CI.BAT: " Patchwork
2025-10-02  2:54 ` ✓ Xe.CI.Full: " Patchwork
2025-10-02 14:10 ` [PATCH] drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans() Rodrigo Vivi
2025-10-03 11:16   ` Nilawar, Badal
2025-10-03 14:21     ` Rodrigo Vivi
  -- strict thread matches above, loose matches on Subject: below --
2025-10-01  1:09 mallesh.koujalagi
2025-10-01 15:29 ` Rodrigo Vivi
2025-10-01  0:53 mallesh.koujalagi

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