* [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
@ 2017-02-13 9:27 ` zain wang
0 siblings, 0 replies; 8+ messages in thread
From: zain wang @ 2017-02-13 9:27 UTC (permalink / raw)
To: Sean Paul, Daniel Vetter, Inki Dae, David Airlie
Cc: linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA, Heiko Stuebner,
Tomeu Vizoso, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
Jingoo Han, dianders-F7+t8E8rja9g9hUCZPvPmw,
dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW, Tomasz Figa,
Javier Martinez Canillas, zain wang, Mika Kahola,
Stéphane Marchesin, Thierry Reding,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
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, &msg);
......
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 <wzz-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
---
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
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
@ 2017-02-20 2:13 ` Zain Wang
0 siblings, 0 replies; 8+ messages in thread
From: Zain Wang @ 2017-02-20 2:13 UTC (permalink / raw)
To: Sean Paul, Daniel Vetter, Inki Dae, David Airlie
Cc: Tomeu Vizoso, Mika Kahola, Stéphane Marchesin, Tomasz Figa,
dianders, Thierry Reding, Heiko Stuebner, Jingoo Han,
Javier Martinez Canillas, linux-kernel, dri-devel,
linux-samsung-soc, linux-rockchip
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, &msg);
> ......
>
> 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 <wzz@rock-chips.com>
> ---
> 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;
> }
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
@ 2017-02-20 2:13 ` Zain Wang
0 siblings, 0 replies; 8+ messages in thread
From: Zain Wang @ 2017-02-20 2:13 UTC (permalink / raw)
To: Sean Paul, Daniel Vetter, Inki Dae, David Airlie
Cc: linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA, Heiko Stuebner,
Tomeu Vizoso, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
Jingoo Han, dianders-F7+t8E8rja9g9hUCZPvPmw,
dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW, Tomasz Figa,
Javier Martinez Canillas, Mika Kahola, Stéphane Marchesin,
Thierry Reding, linux-kernel-u79uwXL29TY76Z2rM5mHXA
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, &msg);
> ......
>
> 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 <wzz@rock-chips.com>
> ---
> 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;
> }
_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
2017-02-13 9:27 ` zain wang
(?)
(?)
@ 2017-02-20 2:40 ` Tomasz Figa
2017-02-20 4:04 ` Zain Wang
-1 siblings, 1 reply; 8+ messages in thread
From: Tomasz Figa @ 2017-02-20 2:40 UTC (permalink / raw)
To: zain wang
Cc: Sean Paul, Daniel Vetter, Inki Dae, David Airlie, Tomeu Vizoso,
Mika Kahola, Stéphane Marchesin, Douglas Anderson,
Thierry Reding, Heiko Stuebner, Jingoo Han,
Javier Martinez Canillas, linux-kernel, dri-devel,
linux-samsung-soc, open list:ARM/Rockchip SoC...
Hi Zain,
On Mon, Feb 13, 2017 at 6:27 PM, zain wang <wzz@rock-chips.com> 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, &msg);
> ......
>
> 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 <wzz@rock-chips.com>
> ---
> 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
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
2017-02-20 2:40 ` Tomasz Figa
@ 2017-02-20 4:04 ` Zain Wang
2017-02-20 4:16 ` Tomasz Figa
0 siblings, 1 reply; 8+ messages in thread
From: Zain Wang @ 2017-02-20 4:04 UTC (permalink / raw)
To: Tomasz Figa
Cc: Sean Paul, Daniel Vetter, Inki Dae, David Airlie, Tomeu Vizoso,
Mika Kahola, Stéphane Marchesin, Douglas Anderson,
Thierry Reding, Heiko Stuebner, Jingoo Han,
Javier Martinez Canillas, linux-kernel, dri-devel,
linux-samsung-soc, open list:ARM/Rockchip SoC...
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 <wzz@rock-chips.com> 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, &msg);
>> ......
>>
>> 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 <wzz@rock-chips.com>
>> ---
>> 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
>
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
2017-02-20 4:04 ` Zain Wang
@ 2017-02-20 4:16 ` Tomasz Figa
0 siblings, 0 replies; 8+ messages in thread
From: Tomasz Figa @ 2017-02-20 4:16 UTC (permalink / raw)
To: Zain Wang
Cc: Sean Paul, Daniel Vetter, Inki Dae, David Airlie, Tomeu Vizoso,
Mika Kahola, Stéphane Marchesin, Douglas Anderson,
Thierry Reding, Heiko Stuebner, Jingoo Han,
Javier Martinez Canillas, linux-kernel, dri-devel,
linux-samsung-soc, open list:ARM/Rockchip SoC...
On Mon, Feb 20, 2017 at 1:04 PM, Zain Wang <wzz@rock-chips.com> wrote:
> 在 2017/2/20 10:40, Tomasz Figa 写道:
>> On Mon, Feb 13, 2017 at 6:27 PM, zain wang <wzz@rock-chips.com> 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
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction
@ 2017-02-20 4:16 ` Tomasz Figa
0 siblings, 0 replies; 8+ messages in thread
From: Tomasz Figa @ 2017-02-20 4:16 UTC (permalink / raw)
To: Zain Wang
Cc: linux-samsung-soc, Tomeu Vizoso, open list:ARM/Rockchip SoC...,
Daniel Vetter, Douglas Anderson, dri-devel, linux-kernel,
Javier Martinez Canillas, Mika Kahola, Jingoo Han,
Stéphane Marchesin, Thierry Reding
On Mon, Feb 20, 2017 at 1:04 PM, Zain Wang <wzz@rock-chips.com> wrote:
> 在 2017/2/20 10:40, Tomasz Figa 写道:
>> On Mon, Feb 13, 2017 at 6:27 PM, zain wang <wzz@rock-chips.com> 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
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 8+ messages in thread