[PATCH 1/4] drm/dp: add flags field to drm_dp_aux_msg struct

[Alex Deucher]

On Fri, Apr 4, 2014 at 2:09 AM, Jani Nikula <jani.nikula at linux.intel.com> wrote:
> On Sat, 22 Mar 2014, Alex Deucher <alexdeucher at gmail.com> wrote:
>> This adds a flags field and a new flag, BARE_ADDRESS,
>> which drivers can use for special handling when they
>> want to set just the aux address.  This is needed
>> to properly reset the connection between i2c transactions.
>
> Sorry it took me so long to get to this.
>
> The changes in patches 1-3 look sensible in general, but I think I'd
> prefer you dropped the flags field and used size == 0 to mean bare
> address. It feels silly to have to set size = 1 and have a dummy one
> byte buffer that doesn't get transfered. Without the payload I think it
> feels natural only the address is transfered.

Thanks.  I'll resend with size = 0.  Note that it doesn't look like
the current intel dp code handles zero sized transfers so that will
need to be fixed up.

Alex


>
> BR,
> Jani.
>
>
>>
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>> ---
>>  include/drm/drm_dp_helper.h | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
>> index b7488c9..a006e96 100644
>> --- a/include/drm/drm_dp_helper.h
>> +++ b/include/drm/drm_dp_helper.h
>> @@ -403,6 +403,8 @@ drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>>   * DisplayPort AUX channel
>>   */
>>
>> +#define DRM_DP_AUX_MSG_FLAGS_BARE_ADDRESS (1 << 0)
>> +
>>  /**
>>   * struct drm_dp_aux_msg - DisplayPort AUX channel transaction
>>   * @address: address of the (first) register to access
>> @@ -417,6 +419,7 @@ struct drm_dp_aux_msg {
>>       u8 reply;
>>       void *buffer;
>>       size_t size;
>> +     u32 flags;
>>  };
>>
>>  /**
>> --
>> 1.8.3.1
>>
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>
> --
> Jani Nikula, Intel Open Source Technology Center