yeah Shuah~ thanks for your reply

For this issue, not meaning "current CPU frequency" but "boost state support--->Active" during 
"cpupower frequency-info" command as below:

	boost state support:
    		Supported: yes
    		Active: yes/no

I think the state returned from the command for amd cpu (family < 0x17) should be like as below:

	as non-root Active state:
		Active: Error while evaluating Boost Capabilities on CPU xx -- are you root?
	
	as root Active state:
		Active: yes (if supported)
			no  (if not supprted)

I don't wanna see the state returned like below:
	
	as non-root Active state:
		Active: yes
	
	as root Active state:
		Active: yes (if supported)
			no  (if not supprted)
	
I will paste the related code by detailed for showing the issue:
	
	if amd cpu family < 0x17 , will run amd_pci_get_num_boost_states function:
-----------------------------------------------------
/linux/tools/power/cpupower/utils/helper/misc.c
 
	if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_CPB) {
		*support = 1;

		/* AMD Family 0x17 does not utilize PCI D18F4 like prior
		 * families and has no fixed discrete boost states but
		 * has Hardware determined variable increments instead.
		 */

		if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_CPB_MSR) {
			if (!read_msr(cpu, MSR_AMD_HWCR, &val)) {
				if (!(val & CPUPOWER_AMD_CPBDIS))
					*active = 1;
			}
		} else {
			ret = amd_pci_get_num_boost_states(active, states);
			if (ret)
				return ret;
		}
---------------------------------------------------

/linux/tools/power/cpupower/utils/helper/amd.c
amd_pci_get_num_boost_states:
	
	val = pci_read_byte(device, 0x15c);

 	if (val & 3)
 		*active = 1;
 	else
----------------------------------------------------

pci_read_byte will memset val to 0xff if caller has no permission to access to read from pci_dev
but for amd_pci_get_num_boost_states, active state will set 1 meaning "yes". I believe that active
state should return negative value to caller function meaning "have no permission" will showing "
Error while evaluating Boost Capabilities on CPU xx -- are you root?"  

----------------------------------------------------
static inline void
pci_read_data(struct pci_dev *d, void *buf, int pos, int len)
{
  if (pos & (len-1))
    d->access->error("Unaligned read: pos=%02x, len=%d", pos, len);
  if (pos + len <= d->cache_len)
    memcpy(buf, d->cache + pos, len);
  else if (!d->methods->read(d, pos, buf, len))
    memset(buf, 0xff, len);
}

byte
pci_read_byte(struct pci_dev *d, int pos)
{
  byte buf;
  pci_read_data(d, &buf, pos, 1);
  return buf;
}
----------------------------------------------------


在 2021/3/24 下午6:27, xufuhai 写道: