--- a/sys/dev/drm/amd/amdgpu/atombios_i2c.c	2026-06-29 12:51:18.000000000 +0000
+++ b/sys/dev/drm/amd/amdgpu/atombios_i2c.c	2026-09-30 15:10:43.316498599 +0000
@@ -169,6 +169,10 @@
 	PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
 	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
 
+	/* DF-5164: match amdgpu_atombios_i2c_process_i2c_ch() and zero the whole
+	 * parameter block before handing it to the atom interpreter. */
+	memset(&args, 0, sizeof(args));
+
 	args.ucRegIndex = offset;
 	args.lpI2CDataOut = data;
 	args.ucFlag = 1;