[PATCH v2 1/2] USB: storage: ums-realtek: Update module parameter description for auto_delink_en

[PATCH v2 1/2] USB: storage: ums-realtek: Update module parameter description for auto_delink_en

[Kai-Heng Feng]

The option named "auto_delink_en" is a bit misleading, as setting it to
false doesn't really disable auto-delink but let auto-delink be firmware
controlled.

Update the description to reflect the real usage of this parameter.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v2:
- Only update module parameter description.

 drivers/usb/storage/realtek_cr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
index cc794e25a0b6..beaffac805af 100644
--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -38,7 +38,7 @@ MODULE_LICENSE("GPL");
 
 static int auto_delink_en = 1;
 module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(auto_delink_en, "enable auto delink");
+MODULE_PARM_DESC(auto_delink_en, "auto delink mode (0=firmware, 1=software [default])");
 
 #ifdef CONFIG_REALTEK_AUTOPM
 static int ss_en = 1;
-- 
2.17.1

[PATCH v2 2/2] USB: storage: ums-realtek: Make auto-delink support optionally

[Kai-Heng Feng]

Auto-delink requires writing special registers to ums-realtek device.
Unconditionally enable auto-delink may break newer devices.

So only enable auto-delink by default for the original three IDs,
0x0138, 0x0158 and 0x0159.

Realtek is working on a patch to properly support auto-delink for other
IDs.

BugLink: https://bugs.launchpad.net/bugs/1838886
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v2:
- Use auto_delink_support instead of auto_delink_enable.

drivers/usb/storage/realtek_cr.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
index beaffac805af..b304cca7c4fa 100644
--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -40,6 +40,10 @@ static int auto_delink_en = 1;
 module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(auto_delink_en, "auto delink mode (0=firmware, 1=software [default])");
 
+static int auto_delink_support = -1;
+module_param(auto_delink_support, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(auto_delink_support, "enable auto delink (-1=auto [default], 0=disable, 1=enable)");
+
 #ifdef CONFIG_REALTEK_AUTOPM
 static int ss_en = 1;
 module_param(ss_en, int, S_IRUGO | S_IWUSR);
@@ -996,12 +1000,22 @@ static int init_realtek_cr(struct us_data *us)
 			goto INIT_FAIL;
 	}
 
-	if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
-	    CHECK_FW_VER(chip, 0x5901))
-		SET_AUTO_DELINK(chip);
-	if (STATUS_LEN(chip) == 16) {
-		if (SUPPORT_AUTO_DELINK(chip))
+	if (auto_delink_support == -1) {
+		if (CHECK_PID(chip, 0x0138) || CHECK_PID(chip, 0x0158) ||
+		    CHECK_PID(chip, 0x0159))
+			auto_delink_support = 1;
+		else
+			auto_delink_support = 0;
+	}
+
+	if (auto_delink_support) {
+		if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
+				CHECK_FW_VER(chip, 0x5901))
 			SET_AUTO_DELINK(chip);
+		if (STATUS_LEN(chip) == 16) {
+			if (SUPPORT_AUTO_DELINK(chip))
+				SET_AUTO_DELINK(chip);
+		}
 	}
 #ifdef CONFIG_REALTEK_AUTOPM
 	if (ss_en)
-- 
2.17.1

Re: [PATCH v2 2/2] USB: storage: ums-realtek: Make auto-delink support optionally

[Alan Stern]

On Mon, 26 Aug 2019, Kai-Heng Feng wrote:

> Auto-delink requires writing special registers to ums-realtek device.
> Unconditionally enable auto-delink may break newer devices.
> 
> So only enable auto-delink by default for the original three IDs,
> 0x0138, 0x0158 and 0x0159.
> 
> Realtek is working on a patch to properly support auto-delink for other
> IDs.
> 
> BugLink: https://bugs.launchpad.net/bugs/1838886
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v2:
> - Use auto_delink_support instead of auto_delink_enable.
> 
> drivers/usb/storage/realtek_cr.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
> index beaffac805af..b304cca7c4fa 100644
> --- a/drivers/usb/storage/realtek_cr.c
> +++ b/drivers/usb/storage/realtek_cr.c
> @@ -40,6 +40,10 @@ static int auto_delink_en = 1;
>  module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
>  MODULE_PARM_DESC(auto_delink_en, "auto delink mode (0=firmware, 1=software [default])");
>  
> +static int auto_delink_support = -1;
> +module_param(auto_delink_support, int, S_IRUGO | S_IWUSR);
> +MODULE_PARM_DESC(auto_delink_support, "enable auto delink (-1=auto [default], 0=disable, 1=enable)");
> +
>  #ifdef CONFIG_REALTEK_AUTOPM
>  static int ss_en = 1;
>  module_param(ss_en, int, S_IRUGO | S_IWUSR);
> @@ -996,12 +1000,22 @@ static int init_realtek_cr(struct us_data *us)
>  			goto INIT_FAIL;
>  	}
>  
> -	if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
> -	    CHECK_FW_VER(chip, 0x5901))
> -		SET_AUTO_DELINK(chip);
> -	if (STATUS_LEN(chip) == 16) {
> -		if (SUPPORT_AUTO_DELINK(chip))
> +	if (auto_delink_support == -1) {
> +		if (CHECK_PID(chip, 0x0138) || CHECK_PID(chip, 0x0158) ||
> +		    CHECK_PID(chip, 0x0159))
> +			auto_delink_support = 1;
> +		else
> +			auto_delink_support = 0;
> +	}

What will happen if somebody has two Realtek devices plugged in, where
one of them has an old product ID and the other has a new one?  You
shouldn't change the value of the module parameter like this.

> +
> +	if (auto_delink_support) {
> +		if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
> +				CHECK_FW_VER(chip, 0x5901))
>  			SET_AUTO_DELINK(chip);
> +		if (STATUS_LEN(chip) == 16) {
> +			if (SUPPORT_AUTO_DELINK(chip))
> +				SET_AUTO_DELINK(chip);
> +		}
>  	}
>  #ifdef CONFIG_REALTEK_AUTOPM
>  	if (ss_en)

Instead of adding a new module parameter, how about just changing the 
driver's behavior?  If a chip doesn't have the right product ID, don't 
enable auto_delink regardless of what the module parameter is set to.

Alan Stern

Re: [PATCH v2 2/2] USB: storage: ums-realtek: Make auto-delink support optionally

[Kai-Heng Feng]

at 23:55, Alan Stern <stern@rowland.harvard.edu> wrote:

> On Mon, 26 Aug 2019, Kai-Heng Feng wrote:
>
>> Auto-delink requires writing special registers to ums-realtek device.
>> Unconditionally enable auto-delink may break newer devices.
>>
>> So only enable auto-delink by default for the original three IDs,
>> 0x0138, 0x0158 and 0x0159.
>>
>> Realtek is working on a patch to properly support auto-delink for other
>> IDs.
>>
>> BugLink: https://bugs.launchpad.net/bugs/1838886
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>> v2:
>> - Use auto_delink_support instead of auto_delink_enable.
>>
>> drivers/usb/storage/realtek_cr.c | 24 +++++++++++++++++++-----
>>  1 file changed, 19 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/usb/storage/realtek_cr.c  
>> b/drivers/usb/storage/realtek_cr.c
>> index beaffac805af..b304cca7c4fa 100644
>> --- a/drivers/usb/storage/realtek_cr.c
>> +++ b/drivers/usb/storage/realtek_cr.c
>> @@ -40,6 +40,10 @@ static int auto_delink_en = 1;
>>  module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
>>  MODULE_PARM_DESC(auto_delink_en, "auto delink mode (0=firmware, 1=software [default])");
>>
>> +static int auto_delink_support = -1;
>> +module_param(auto_delink_support, int, S_IRUGO | S_IWUSR);
>> +MODULE_PARM_DESC(auto_delink_support, "enable auto delink (-1=auto  
>> [default], 0=disable, 1=enable)");
>> +
>>  #ifdef CONFIG_REALTEK_AUTOPM
>>  static int ss_en = 1;
>>  module_param(ss_en, int, S_IRUGO | S_IWUSR);
>> @@ -996,12 +1000,22 @@ static int init_realtek_cr(struct us_data *us)
>>  			goto INIT_FAIL;
>>  	}
>>
>> -	if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
>> -	    CHECK_FW_VER(chip, 0x5901))
>> -		SET_AUTO_DELINK(chip);
>> -	if (STATUS_LEN(chip) == 16) {
>> -		if (SUPPORT_AUTO_DELINK(chip))
>> +	if (auto_delink_support == -1) {
>> +		if (CHECK_PID(chip, 0x0138) || CHECK_PID(chip, 0x0158) ||
>> +		    CHECK_PID(chip, 0x0159))
>> +			auto_delink_support = 1;
>> +		else
>> +			auto_delink_support = 0;
>> +	}
>
> What will happen if somebody has two Realtek devices plugged in, where
> one of them has an old product ID and the other has a new one?  You
> shouldn't change the value of the module parameter like this.

You are right, I didn’t think of that.

>
>> +
>> +	if (auto_delink_support) {
>> +		if (CHECK_FW_VER(chip, 0x5888) || CHECK_FW_VER(chip, 0x5889) ||
>> +				CHECK_FW_VER(chip, 0x5901))
>>  			SET_AUTO_DELINK(chip);
>> +		if (STATUS_LEN(chip) == 16) {
>> +			if (SUPPORT_AUTO_DELINK(chip))
>> +				SET_AUTO_DELINK(chip);
>> +		}
>>  	}
>>  #ifdef CONFIG_REALTEK_AUTOPM
>>  	if (ss_en)
>
> Instead of adding a new module parameter, how about just changing the
> driver's behavior?  If a chip doesn't have the right product ID, don't
> enable auto_delink regardless of what the module parameter is set to.

Ok, I think whitelist is a better approach until Realtek comes up with a  
long term solution.

Kai-Heng

>
> Alan Stern