On 08/06/2025, Luca Ceresoli wrote:
> On Wed, 6 Aug 2025 17:38:17 +0800
> Liu Ying <victor....@nxp.com> wrote:
>
>> On 08/06/2025, Luca Ceresoli wrote:
>>> Hello Liu,
>>>
>>> On Wed, 6 Aug 2025 16:54:24 +0800
>>> Liu Ying <victor....@nxp.com> wrote:
>>>
>>>> devm_drm_bridge_alloc() returns ERR_PTR on failure instead of a
>>>> NULL pointer, so use IS_ERR() to check the returned pointer.
>>>>
>>>> Fixes: 48f05c3b4b70 ("drm/bridge: analogix_dp: Use devm_drm_bridge_alloc()
>>>> API")
>>>> Signed-off-by: Liu Ying <victor....@nxp.com>
>>>> ---
>>>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>>> index ed35e567d117..86cf898a09bb 100644
>>>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>>> @@ -1474,7 +1474,7 @@ analogix_dp_probe(struct device *dev, struct
>>>> analogix_dp_plat_data *plat_data)
>>>>
>>>> dp = devm_drm_bridge_alloc(dev, struct analogix_dp_device, bridge,
>>>> &analogix_dp_bridge_funcs);
>>>> - if (!dp)
>>>> + if (IS_ERR(dp))
>>>> return ERR_PTR(-ENOMEM);
>>>
>>> Good catch, thanks!
>>>
>>> You fix is correct but now I realized one additional fix is needed in
>>> the following line:
>>>
>>> - return ERR_PTR(-ENOMEM);
>>> + return ERR_PTR(dp);
>>
>> You mean ERR_CAST(dp)?
>
> Ah, indeed!
>
>>> Can you send a v2 with that fixed?
>>
>> I find devm_drm_bridge_alloc() always returns ERR_PTR(-ENOMEM) in this
>> driver context, so it seems fine to keep the existing ERR_PTR(-ENOMEM).
>> If you prefer ERR_CAST(dp), I may send v2 to use ERR_CAST(dp).
>
> The documentation says:
>
> * Returns:
> * Pointer to new bridge, or ERR_PTR on failure.
>
> So let's follow that, which is a (relatively) immutable contract, and
> not the implementation which might change over time.
Fair enough. v2 is on the way.
>
> This is also what all callers of devm_drm_bridge_alloc() do, unless I
> missed something.
>
> Thanks,
> Luca
>
--
Regards,
Liu Ying
