Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Tomasz Figa 
On Mon, Feb 20, 2017 at 1:04 PM, Zain Wang  wrote:
> 在 2017/2/20 10:40, Tomasz Figa 写道:
>> On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:
>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> index 303083a..5384aca 100644
>>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> @@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct
>>> analogix_dp_device *dp,
>>>   (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
>>>  msg->reply = DP_AUX_NATIVE_REPLY_ACK;
>>>
>>> -   return num_transferred > 0 ? num_transferred : -EBUSY;
>>> +   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
>>
>> I might be missing something but, looking at the code, I don't see any
>> possibility of num_transferred ever being different than msg->size. To
>> be honest, it doesn't seem to even make any sense keeping the local
>> variable there, because msg->size can be simply always returned, as
>> errors are handled by jumping to aux_error label.
>
> Yeah, I agree with you.
> The better way to fix this issue is to revert the changes
> https://patchwork.kernel.org/patch/9411711/
> (returning num_transferred directly may be better here)

I think it's still not enough to clean up the code completely. It
should be just enough to remove num_transferred completely and simply
return msg->size at the end.

Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Tomasz Figa 
On Mon, Feb 20, 2017 at 1:04 PM, Zain Wang  wrote:
> 在 2017/2/20 10:40, Tomasz Figa 写道:
>> On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:
>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> index 303083a..5384aca 100644
>>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
>>> @@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct
>>> analogix_dp_device *dp,
>>>   (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
>>>  msg->reply = DP_AUX_NATIVE_REPLY_ACK;
>>>
>>> -   return num_transferred > 0 ? num_transferred : -EBUSY;
>>> +   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
>>
>> I might be missing something but, looking at the code, I don't see any
>> possibility of num_transferred ever being different than msg->size. To
>> be honest, it doesn't seem to even make any sense keeping the local
>> variable there, because msg->size can be simply always returned, as
>> errors are handled by jumping to aux_error label.
>
> Yeah, I agree with you.
> The better way to fix this issue is to revert the changes
> https://patchwork.kernel.org/patch/9411711/
> (returning num_transferred directly may be better here)

I think it's still not enough to clean up the code completely. It
should be just enough to remove num_transferred completely and simply
return msg->size at the end.

Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Zain Wang 

Hi Tomasz,

在 2017/2/20 10:40, Tomasz Figa 写道:

Hi Zain,

On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:

The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
 ..
 /* Send a bare address packet to start the transaction.
  * Zero sized messages specify an address only (bare
  * address) transaction.
  */
 msg.buffer = NULL;
 msg.size = 0;
 err = drm_dp_i2c_do_msg(aux, );
 ..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.


Please see my question inline.


Signed-off-by: zain wang 
---
  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
  (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
 msg->reply = DP_AUX_NATIVE_REPLY_ACK;

-   return num_transferred > 0 ? num_transferred : -EBUSY;
+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;

I might be missing something but, looking at the code, I don't see any
possibility of num_transferred ever being different than msg->size. To
be honest, it doesn't seem to even make any sense keeping the local
variable there, because msg->size can be simply always returned, as
errors are handled by jumping to aux_error label.

Yeah, I agree with you.
The better way to fix this issue is to revert the changes 
https://patchwork.kernel.org/patch/9411711/

(returning num_transferred directly may be better here)

Maybe we can revert the changes above with some new comment.
@Sean, How do you think about Tomasz's comment?

Thanks
Zain


Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Zain Wang 

Hi Tomasz,

在 2017/2/20 10:40, Tomasz Figa 写道:

Hi Zain,

On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:

The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
 ..
 /* Send a bare address packet to start the transaction.
  * Zero sized messages specify an address only (bare
  * address) transaction.
  */
 msg.buffer = NULL;
 msg.size = 0;
 err = drm_dp_i2c_do_msg(aux, );
 ..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.


Please see my question inline.


Signed-off-by: zain wang 
---
  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
  (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
 msg->reply = DP_AUX_NATIVE_REPLY_ACK;

-   return num_transferred > 0 ? num_transferred : -EBUSY;
+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;

I might be missing something but, looking at the code, I don't see any
possibility of num_transferred ever being different than msg->size. To
be honest, it doesn't seem to even make any sense keeping the local
variable there, because msg->size can be simply always returned, as
errors are handled by jumping to aux_error label.

Yeah, I agree with you.
The better way to fix this issue is to revert the changes 
https://patchwork.kernel.org/patch/9411711/

(returning num_transferred directly may be better here)

Maybe we can revert the changes above with some new comment.
@Sean, How do you think about Tomasz's comment?

Thanks
Zain


Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Tomasz Figa 
Hi Zain,

On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:
>
> The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
> But sometimes we will send a bare address packet to start the transaction,
> like drm_dp_i2c_xfer() show:
> ..
> /* Send a bare address packet to start the transaction.
>  * Zero sized messages specify an address only (bare
>  * address) transaction.
>  */
> msg.buffer = NULL;
> msg.size = 0;
> err = drm_dp_i2c_do_msg(aux, );
> ..
>
> In this case, the msg->size is zero, so the num_transferred will be zero too.
> We can't return -EBUSY here, let's we return num_transferred if 
> num_transferred
> equals msg->size.
>

Please see my question inline.

> Signed-off-by: zain wang 
> ---
>  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
> b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> index 303083a..5384aca 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> @@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
> *dp,
>  (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
> msg->reply = DP_AUX_NATIVE_REPLY_ACK;
>
> -   return num_transferred > 0 ? num_transferred : -EBUSY;
> +   return (num_transferred == msg->size) ? num_transferred : -EBUSY;

I might be missing something but, looking at the code, I don't see any
possibility of num_transferred ever being different than msg->size. To
be honest, it doesn't seem to even make any sense keeping the local
variable there, because msg->size can be simply always returned, as
errors are handled by jumping to aux_error label.

Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Tomasz Figa 
Hi Zain,

On Mon, Feb 13, 2017 at 6:27 PM, zain wang  wrote:
>
> The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
> But sometimes we will send a bare address packet to start the transaction,
> like drm_dp_i2c_xfer() show:
> ..
> /* Send a bare address packet to start the transaction.
>  * Zero sized messages specify an address only (bare
>  * address) transaction.
>  */
> msg.buffer = NULL;
> msg.size = 0;
> err = drm_dp_i2c_do_msg(aux, );
> ..
>
> In this case, the msg->size is zero, so the num_transferred will be zero too.
> We can't return -EBUSY here, let's we return num_transferred if 
> num_transferred
> equals msg->size.
>

Please see my question inline.

> Signed-off-by: zain wang 
> ---
>  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
> b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> index 303083a..5384aca 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> @@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
> *dp,
>  (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
> msg->reply = DP_AUX_NATIVE_REPLY_ACK;
>
> -   return num_transferred > 0 ? num_transferred : -EBUSY;
> +   return (num_transferred == msg->size) ? num_transferred : -EBUSY;

I might be missing something but, looking at the code, I don't see any
possibility of num_transferred ever being different than msg->size. To
be honest, it doesn't seem to even make any sense keeping the local
variable there, because msg->size can be simply always returned, as
errors are handled by jumping to aux_error label.

Best regards,
Tomasz

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Zain Wang 

Hi Sean,

Could you give some comments for this patch?

Thanks
Zain


在 2017/2/13 17:27, zain wang 写道:

The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
..
/* Send a bare address packet to start the transaction.
 * Zero sized messages specify an address only (bare
 * address) transaction.
 */
msg.buffer = NULL;
msg.size = 0;
err = drm_dp_i2c_do_msg(aux, );
..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.

Signed-off-by: zain wang 
---
  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
msg->reply = DP_AUX_NATIVE_REPLY_ACK;
  
-	return num_transferred > 0 ? num_transferred : -EBUSY;

+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
  }

Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-19 Thread Zain Wang 

Hi Sean,

Could you give some comments for this patch?

Thanks
Zain


在 2017/2/13 17:27, zain wang 写道:

The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
..
/* Send a bare address packet to start the transaction.
 * Zero sized messages specify an address only (bare
 * address) transaction.
 */
msg.buffer = NULL;
msg.size = 0;
err = drm_dp_i2c_do_msg(aux, );
..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.

Signed-off-by: zain wang 
---
  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
msg->reply = DP_AUX_NATIVE_REPLY_ACK;
  
-	return num_transferred > 0 ? num_transferred : -EBUSY;

+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
  }

[PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-13 Thread zain wang 
The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
..
/* Send a bare address packet to start the transaction.
 * Zero sized messages specify an address only (bare
 * address) transaction.
 */
msg.buffer = NULL;
msg.size = 0;
err = drm_dp_i2c_do_msg(aux, );
..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.

Signed-off-by: zain wang 
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
msg->reply = DP_AUX_NATIVE_REPLY_ACK;
 
-   return num_transferred > 0 ? num_transferred : -EBUSY;
+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
 }
-- 
1.9.1

[PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction

2017-02-13 Thread zain wang 
The analogix_dp_transfer() will return -EBUSY if num_transferred is zero.
But sometimes we will send a bare address packet to start the transaction,
like drm_dp_i2c_xfer() show:
..
/* Send a bare address packet to start the transaction.
 * Zero sized messages specify an address only (bare
 * address) transaction.
 */
msg.buffer = NULL;
msg.size = 0;
err = drm_dp_i2c_do_msg(aux, );
..

In this case, the msg->size is zero, so the num_transferred will be zero too.
We can't return -EBUSY here, let's we return num_transferred if num_transferred
equals msg->size.

Signed-off-by: zain wang 
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 303083a..5384aca 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device 
*dp,
 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
msg->reply = DP_AUX_NATIVE_REPLY_ACK;
 
-   return num_transferred > 0 ? num_transferred : -EBUSY;
+   return (num_transferred == msg->size) ? num_transferred : -EBUSY;
 }
-- 
1.9.1