[PATCH] ACPI / EC: Use busy polling mode when GPE is not enabled

[PATCH] ACPI / EC: Use busy polling mode when GPE is not enabled

[Chen Yu]

From: Lv Zheng <lv.zheng@intel.com>

Previously we have report that during system bootup, the EC command
was running too slow because the EC GPE has not been enabled yet
(For example, _REG tries to access the EC operation region, while the
EC GPE has not been enabled at that stage). Actually we can optimize this
scenario by using busy polling mode if GPE is disabled, which is much
faster than the default behavior.

Reported-and-tested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 drivers/acpi/ec.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 48e19d0..457949d 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -342,6 +342,14 @@ static const char *acpi_ec_cmd_string(u8 cmd)
  *                           GPE Registers
  * -------------------------------------------------------------------------- */
 
+static inline bool acpi_ec_is_gpe_enabled(struct acpi_ec *ec)
+{
+	acpi_event_status gpe_status = 0;
+
+	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
+	return (gpe_status & ACPI_EVENT_FLAG_ENABLE_SET) ? true : false;
+}
+
 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 {
 	acpi_event_status gpe_status = 0;
@@ -734,7 +742,7 @@ static int ec_guard(struct acpi_ec *ec)
 
 	/* Ensure guarding period before polling EC status */
 	do {
-		if (ec_busy_polling) {
+		if (!acpi_ec_is_gpe_enabled(ec) || ec_busy_polling) {
 			/* Perform busy polling */
 			if (ec_transaction_completed(ec))
 				return 0;
-- 
2.7.4

RE: [PATCH] ACPI / EC: Use busy polling mode when GPE is not enabled

[Zheng, Lv]

Hi, Yu

> From: Chen, Yu C
> Subject: [PATCH] ACPI / EC: Use busy polling mode when GPE is not enabled
> 
> From: Lv Zheng <lv.zheng@intel.com>
> 
> Previously we have report that during system bootup, the EC command
> was running too slow because the EC GPE has not been enabled yet
> (For example, _REG tries to access the EC operation region, while the
> EC GPE has not been enabled at that stage). Actually we can optimize this
> scenario by using busy polling mode if GPE is disabled, which is much
> faster than the default behavior.

I suddenly realized that why I didn't put this check during my previous EC work.
Though this patch can solve the issue in question, it doesn't handle runtime EC polling in a proper way.
Sorry for my damaged memory.

Let me provide a different fix.
So please drop it.

Thanks and best regards
Lv

> 
> Reported-and-tested-by: Chen Yu <yu.c.chen@intel.com>
> Signed-off-by: Lv Zheng <lv.zheng@intel.com>
> ---
>  drivers/acpi/ec.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
> index 48e19d0..457949d 100644
> --- a/drivers/acpi/ec.c
> +++ b/drivers/acpi/ec.c
> @@ -342,6 +342,14 @@ static const char *acpi_ec_cmd_string(u8 cmd)
>   *                           GPE Registers
>   * -------------------------------------------------------------------------- */
> 
> +static inline bool acpi_ec_is_gpe_enabled(struct acpi_ec *ec)
> +{
> +	acpi_event_status gpe_status = 0;
> +
> +	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
> +	return (gpe_status & ACPI_EVENT_FLAG_ENABLE_SET) ? true : false;
> +}
> +
>  static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
>  {
>  	acpi_event_status gpe_status = 0;
> @@ -734,7 +742,7 @@ static int ec_guard(struct acpi_ec *ec)
> 
>  	/* Ensure guarding period before polling EC status */
>  	do {
> -		if (ec_busy_polling) {
> +		if (!acpi_ec_is_gpe_enabled(ec) || ec_busy_polling) {
>  			/* Perform busy polling */
>  			if (ec_transaction_completed(ec))
>  				return 0;
> --
> 2.7.4