THE ACPI spec states:
"[The Error status register] Contains the processor relative address,
represented in Generic Address Structure (GAS) format, of the Error status
register. This field is ignored by the OSPM on slave channels"
Which Refers to type 4 channels.
https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/14_Platform_Communications_Channel/Platform_Comm_Channel.html#hw-registers-based-communications-subspace-structure-type-5
Signed-off-by: Adam Young <admiyo@os.amperecomputing.com>
---
drivers/mailbox/pcc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 636879ae1db7..0deaf7907ed6 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -270,6 +270,9 @@ static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
u64 val;
int ret;
+ if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+ return 0;
+
ret = pcc_chan_reg_read(&pchan->error, &val);
if (ret)
return ret;
--
2.43.0