diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c index 84f1ac416b57..16ba875e3293 100644 --- a/drivers/acpi/acpi_pcc.c +++ b/drivers/acpi/acpi_pcc.c @@ -23,6 +23,12 @@ #include +/* + * Arbitrary retries in case the remote processor is slow to respond + * to PCC commands + */ +#define PCC_CMD_WAIT_RETRIES_NUM 500 + struct pcc_data { struct pcc_mbox_chan *pcc_chan; void __iomem *pcc_comm_addr; @@ -89,6 +95,7 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, { int ret; struct pcc_data *data = region_context; + u64 usecs_lat; reinit_completion(&data->done); @@ -99,8 +106,20 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, if (ret < 0) return AE_ERROR; - if (data->pcc_chan->mchan->mbox->txdone_irq) - wait_for_completion(&data->done); + if (data->pcc_chan->mchan->mbox->txdone_irq) { + /* + * pcc_chan->latency is just a Nominal value. In reality the remote + * processor could be much slower to reply. So add an arbitrary + * amount of wait on top of Nominal. + */ + usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency; + ret = wait_for_completion_timeout(&data->done, + usecs_to_jiffies(usecs_lat)); + if (ret == 0) { + pr_err("PCC command executed timeout!\n"); + return AE_TIME; + } + } mbox_client_txdone(data->pcc_chan->mchan, ret);