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drm/xe/xe_late_bind_fw: Initialize uval variable in xe_late_bind_fw_num_fans()

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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: 45832bf9c1 ("drm/xe/xe_late_bind_fw: Initialize late binding firmware")
Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
Link: https://lore.kernel.org/r/20251002005648.3185636-1-mallesh.koujalagi@intel.com
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
(cherry picked from commit 07abc16c14)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
This commit is contained in:
Mallesh Koujalagi 2025-10-02 06:26:48 +05:30 committed by Lucas De Marchi
parent 10aa5c8060
commit 6982a462cb
1 changed files with 8 additions and 8 deletions
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16
drivers/gpu/drm/xe/xe_late_bind_fw.c
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@ -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;