Re: [PATCH v4 3/3] drm/vc4: dsi: remove unnecessary intermediate pointer computation

[Luca Ceresoli]

Hello Maíra,

On Fri Nov 6, 2026 at 12:27 AM CET, Maíra Canal wrote:
> Hi Luca,
>
> On 05/11/26 07:32, Luca Ceresoli wrote:
>> This function computes the 'dsi' pointer from the passed 'bridge' pointer,
>> but uses 'dsi' just to obtain the same 'bridge' pointer. Remove the
>> unnecessary pointer dance, just use the passed 'bridge' pointer.
>>
>> Suggested-by: Maíra Canal <mcanal@xxxxxxxxxx>
>> Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
>>
>> ---
>>
>> New patch in v4
>> ---
>>   drivers/gpu/drm/vc4/vc4_dsi.c | 5 +----
>>   1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
>> index 581b54e04ce4..ec008f766dd5 100644
>> --- a/drivers/gpu/drm/vc4/vc4_dsi.c
>> +++ b/drivers/gpu/drm/vc4/vc4_dsi.c
>> @@ -1159,10 +1159,7 @@ static int vc4_dsi_bridge_attach(struct drm_bridge *bridge,
>>   				 struct drm_encoder *encoder,
>>   				 enum drm_bridge_attach_flags flags)
>>   {
>> -	struct vc4_dsi *dsi = bridge_to_vc4_dsi(bridge);
>> -
>> -	return drm_bridge_attach(encoder, dsi->bridge.next_bridge,
>> -				 &dsi->bridge, flags);
>> +	return drm_bridge_attach(encoder, bridge->next_bridge, bridge, flags);
>
> I wonder if we should turn this into a DRM helper... I noticed that
> other drivers follow this exact same pattern. The following files have
> such pattern: vs_bridge.c, meson_encoder_hdmi.c, rzg2l_mipi_dsi.c, etc.

Good point. I also think this could be factored out to a common
function. However for the time being I haven't done any steps in that
direction because I'm soon going to propose a .get_next_bridge bridge func
in [0], and I suspect that addition could further improve bridge attach
management. So I'm waiting until the get_next_bridge work is settled before
doing further steps.

> Anyway, just a suggestion. I already pushed the series to drm-misc-next.

Thanks!

[0] https://lore.kernel.org/lkml/20261001-drm-bridge-hotplug-v2-17-8e34986dcb68@xxxxxxxxxxx/

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com