linux-kernel - Re: [PATCH v7 drm-dp 5/9] drm/hisilicon/hibmc: Getting connector info and EDID by using AUX channel

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Message-ID: <808ab7db-b42d-4510-8b07-99ed96aef1f0@huawei.com>
Date: Sat, 29 Mar 2025 14:12:56 +0800
From: Yongbang Shi <shiyongbang@...wei.com>
To: Maxime Ripard <mripard@...nel.org>, Jani Nikula
	<jani.nikula@...ux.intel.com>
CC: <xinliang.liu@...aro.org>, <tiantao6@...ilicon.com>,
	<maarten.lankhorst@...ux.intel.com>, <tzimmermann@...e.de>,
	<airlied@...il.com>, <daniel@...ll.ch>, <kong.kongxinwei@...ilicon.com>,
	<liangjian010@...wei.com>, <chenjianmin@...wei.com>,
	<lidongming5@...wei.com>, <libaihan@...wei.com>, <shenjian15@...wei.com>,
	<shaojijie@...wei.com>, <dri-devel@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <shiyongbang@...wei.com>
Subject: Re: [PATCH v7 drm-dp 5/9] drm/hisilicon/hibmc: Getting connector info
 and EDID by using AUX channel

> On Fri, Mar 28, 2025 at 12:28:14PM +0200, Jani Nikula wrote:
>> On Fri, 28 Mar 2025, Yongbang Shi <shiyongbang@...wei.com> wrote:
>>>> On Thu, 27 Mar 2025, Yongbang Shi <shiyongbang@...wei.com> wrote:
>>>>> 在 2025/3/26 17:32, Jani Nikula 写道:
>>>>>> On Tue, 25 Mar 2025, Yongbang Shi <shiyongbang@...wei.com> wrote:
>>>>>>>> On Mon, 24 Mar 2025, Yongbang Shi <shiyongbang@...wei.com> wrote:
>>>>>>>>>> On Wed, 19 Mar 2025, Yongbang Shi <shiyongbang@...wei.com> wrote:
>>>>>>>>>>> From: Baihan Li <libaihan@...wei.com>
>>>>>>>>>>>
>>>>>>>>>>> Add registering drm_aux and use it to get connector edid with drm
>>>>>>>>>>> functions. Add ddc channel in connector initialization to put drm_aux
>>>>>>>>>>> in drm_connector.
>>>>>>>>>>>
>>>>>>>>>>> Signed-off-by: Baihan Li <libaihan@...wei.com>
>>>>>>>>>>> Signed-off-by: Yongbang Shi <shiyongbang@...wei.com>
>>>>>>>>>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
>>>>>>>>>>> ---
>>>>>>>>>>> ChangeLog:
>>>>>>>>>>> v6 -> v7:
>>>>>>>>>>>        - add if statement about drm aux in hibmc_dp_connector_get_modes(), suggested by Jani Nikula
>>>>>>>>>> I don't understand this, and I did not suggest such a thing.
>>>>>>>>>>
>>>>>>>>>> BR,
>>>>>>>>>> Jani.
>>>>>>>>>>
>>>>>>>>> Hi Jani,
>>>>>>>>>
>>>>>>>>> Is the modification of v8 correct?
>>>>>>>> I never received that for whatever reason.
>>>>>>> Here's the link: https://lore.kernel.org/all/20250320101455.2538835-1-shiyongbang@huawei.com/
>>>>>> Thanks.
>>>>>>
>>>>>> The EDID handling looks fine.
>>>>>>
>>>>>> AFAICT you leak dp->aux.name though.
>>>>>>
>>>>>>
>>>>>> BR,
>>>>>> Jani.
>>>>> Thanks for for reminding me, actually the dp->aux.name was written because I misunderstood what you meant in V7,
>>>>> and I deleted it in V8.
>>>> This is in the link you posted:
>>>>
>>>> +	dp->aux.name = kasprintf(GFP_KERNEL, "HIBMC DRM dp aux");
>>>>
>>> Hi Jani,
>>>
>>> I got it. I think I can change it to devm_kasprintf() in next bug fix patch, is that ok?
>> Maybe. I don't have the time to look into hibmc details.
> I don't either, but it looks suspicious to me. devm_kasprintf will be
> freed when the device will be removed, but the DP Aux bus is probably
> staying for a bit longer?
>
> Maxime

Hi Ripard,

I will bind it to my hibmc device, and aux_unregister is in early_unregister callback of dp's connector_funcs,
which is before the hibmc_pci_remove(), so I think it work good.