[bug report] drm/amd/powerplay: add vce state tables initialize for ppt v1.

[Zhu, Rex]

Thanks, please help to review the attached patch.

Best Regards
Rex

-----Original Message-----
From: Dan Carpenter [mailto:dan.carpenter at oracle.com] 
Sent: Thursday, October 13, 2016 9:26 PM
To: Zhu, Rex
Cc: dri-devel at lists.freedesktop.org
Subject: [bug report] drm/amd/powerplay: add vce state tables initialize for ppt v1.

Hello Rex Zhu,

The patch 48d7b759a8bc: "drm/amd/powerplay: add vce state tables initialize for ppt v1." from Aug 31, 2016, leads to the following static checker warning:

	drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/process_pptables_v1_0.c:1211 ppt_get_num_of_vce_state_table_entries_v1_0()
	warn: 'vce_state_table' can't be NULL.

drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/process_pptables_v1_0.c
  1200
  1201  static int ppt_get_num_of_vce_state_table_entries_v1_0(struct pp_hwmgr *hwmgr)
  1202  {
  1203          const ATOM_Tonga_POWERPLAYTABLE *pp_table = get_powerplay_table(hwmgr);
  1204          const ATOM_Tonga_VCE_State_Table *vce_state_table =
  1205                                  (ATOM_Tonga_VCE_State_Table *)(((unsigned long)pp_table) + le16_to_cpu(pp_table->usVCEStateTableOffset));
                                                                                                               ^^^^^^^^ pp_table can't be NULL because we're dereferencing it here.  That means vce_state_table can't be NULL either.

  1206  
  1207          if (vce_state_table == NULL)
  1208                  return 0;
  1209  
  1210          return vce_state_table->ucNumEntries;
  1211  }
  1212  

A cleaner way to write this is maybe:

static int ppt_get_num_of_vce_state_table_entries_v1_0(struct pp_hwmgr *hwmgr) {
	const ATOM_Tonga_POWERPLAYTABLE *pp_table = get_powerplay_table(hwmgr);
	const ATOM_Tonga_VCE_State_Table *vce_state_table;

	if (!pp_table)
		return 0;

	vce_state_table = (void *)pp_table + le16_to_cpu(pp_table->usVCEStateTableOffset);
	return vce_state_table->ucNumEntries;
}

regards,
dan carpenter
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