From: Jani Nikula <jani.nikula@linux.intel.com>
To: Doug Anderson <dianders@chromium.org>,
Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Neil Armstrong <neil.armstrong@linaro.org>,
Jessica Zhang <quic_jesszhan@quicinc.com>,
Sam Ravnborg <sam@ravnborg.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 1/6] drm_edid: Add a function to get EDID base block
Date: Thu, 07 Mar 2024 14:50:17 +0200 [thread overview]
Message-ID: <87wmqew6ie.fsf@intel.com> (raw)
In-Reply-To: <CAD=FV=XcMRLvSU+_QrNMSOo4JH0hPmA-F3HFjOBj=QwHHQy_mA@mail.gmail.com>
On Wed, 06 Mar 2024, Doug Anderson <dianders@chromium.org> wrote:
> Hi,
>
> On Wed, Mar 6, 2024 at 12:04 PM Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>>
>> @@ -2764,58 +2764,71 @@ static u32 edid_extract_panel_id(const struct edid *edid)
>> }
>>
>> /**
>> - * drm_edid_get_panel_id - Get a panel's ID through DDC
>> - * @adapter: I2C adapter to use for DDC
>> + * drm_edid_get_panel_id - Get a panel's ID from EDID
>> + * @drm_edid: EDID that contains panel ID.
>> *
>> - * This function reads the first block of the EDID of a panel and (assuming
>> + * This function uses the first block of the EDID of a panel and (assuming
>> * that the EDID is valid) extracts the ID out of it. The ID is a 32-bit value
>> * (16 bits of manufacturer ID and 16 bits of per-manufacturer ID) that's
>> * supposed to be different for each different modem of panel.
>> *
>> + * Return: A 32-bit ID that should be different for each make/model of panel.
>> + * See the functions drm_edid_encode_panel_id() and
>> + * drm_edid_decode_panel_id() for some details on the structure of this
>> + * ID.
>> + */
>> +u32 drm_edid_get_panel_id(const struct drm_edid *drm_edid)
>> +{
>
> I'd leave it up to Jani, but I'd wonder whether we need to confirm
> drm_edid->size here is at least as big as the base block. In other
> words: is there ever any chance that someone would have allocated a
> struct drm_edid but not actually read a full base block into it?
On the one hand, I've tried to make all the drm_edid based interfaces
handle all the cases (drm_edid == NULL, drm_edid->edid == NULL,
drm_edid->size < required) gracefully, but on the other hand, panel-edp
is the only user and this would go boom for you quickly if you passed in
a bogus drm_edid.
Adding the checks is definitely not wrong, but I'm not insisting.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
>
> In any case:
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
--
Jani Nikula, Intel
next prev parent reply other threads:[~2024-03-07 12:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 19:55 [PATCH v5 0/6] Match panel with identity Hsin-Yi Wang
2024-03-06 19:55 ` [PATCH v5 1/6] drm_edid: Add a function to get EDID base block Hsin-Yi Wang
2024-03-06 23:29 ` Doug Anderson
2024-03-07 12:50 ` Jani Nikula [this message]
2024-03-06 19:55 ` [PATCH v5 2/6] drm/edid: Clean up drm_edid_get_panel_id() Hsin-Yi Wang
2024-03-06 23:29 ` Doug Anderson
2024-03-07 12:51 ` Jani Nikula
2024-03-06 19:55 ` [PATCH v5 3/6] drm/edid: Add a function to match EDID with identity Hsin-Yi Wang
2024-03-06 23:29 ` Doug Anderson
2024-03-07 0:20 ` Hsin-Yi Wang
2024-03-07 0:37 ` Doug Anderson
2024-03-07 13:20 ` Jani Nikula
2024-03-07 19:34 ` Hsin-Yi Wang
2024-03-07 22:36 ` Jani Nikula
2024-03-06 19:55 ` [PATCH v5 4/6] drm/edid: Match edid quirks " Hsin-Yi Wang
2024-03-06 23:29 ` Doug Anderson
2024-03-06 19:55 ` [PATCH v5 5/6] drm/panel-edp: Match edp_panels with panel identity Hsin-Yi Wang
2024-03-06 23:30 ` Doug Anderson
2024-03-06 19:55 ` [PATCH v5 6/6] drm/panel-edp: Fix AUO 0x405c panel naming and add a variant Hsin-Yi Wang
2024-03-06 23:30 ` Doug Anderson
2024-03-07 13:28 ` Jani Nikula
2024-03-07 20:18 ` Hsin-Yi Wang
2024-03-07 20:27 ` Jani Nikula
2024-03-07 21:46 ` Doug Anderson
2024-03-07 22:35 ` Jani Nikula
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