linux-kernel - Re: [PATCH RFC 1/5] drm/edid: Add support to get edid early

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Date:	Mon, 17 Aug 2015 10:44:49 +0100
From:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:	Jani Nikula <jani.nikula@...ux.intel.com>,
	Thierry Reding <thierry.reding@...il.com>,
	dri-devel@...ts.freedesktop.org
CC:	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC 1/5] drm/edid: Add support to get edid early

On 17/08/15 08:52, Jani Nikula wrote:
> On Fri, 14 Aug 2015, Srinivas Kandagatla <srinivas.kandagatla@...aro.org> wrote:
>> This patch adds support to get edid way early before the connector is
>> created, this is mainly used for panel drivers to auto-probe the panel
>> based on the vendor and product id from EDID.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>> ---
>>   drivers/gpu/drm/drm_edid.c | 8 ++++++++
>>   include/drm/drm_crtc.h     | 1 +
>>   2 files changed, 9 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 7087da3..30359cd 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -1388,6 +1388,14 @@ struct edid *drm_get_edid(struct drm_connector *connector,
>>   }
>>   EXPORT_SYMBOL(drm_get_edid);
>>
>> +struct edid *drm_get_edid_early(struct i2c_adapter *adapter)
>> +{
>> +	struct drm_connector dummy_connector;
>> +
>> +	return drm_get_edid(&dummy_connector, adapter);
>
> This will oops the kernel on bad EDID.
>
Thanks for quick review,

Yes, you are right it would blow up on dev_warn(connector->dev->dev, ...

May we can fix this if we are happy to take this approach of getting 
edid early.

--srini
> BR,
> Jani.
>
>
>> +}
>> +EXPORT_SYMBOL(drm_get_edid_early);
>> +
>>   /**
>>    * drm_edid_duplicate - duplicate an EDID and the extensions
>>    * @edid: EDID to duplicate
>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>> index 57ca8cc..35d8763 100644
>> --- a/include/drm/drm_crtc.h
>> +++ b/include/drm/drm_crtc.h
>> @@ -1330,6 +1330,7 @@ extern void drm_reinit_primary_mode_group(struct drm_device *dev);
>>   extern bool drm_probe_ddc(struct i2c_adapter *adapter);
>>   extern struct edid *drm_get_edid(struct drm_connector *connector,
>>   				 struct i2c_adapter *adapter);
>> +extern struct edid *drm_get_edid_early(struct i2c_adapter *adapter);
>>   extern struct edid *drm_edid_duplicate(const struct edid *edid);
>>   extern int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid);
>>   extern void drm_mode_config_init(struct drm_device *dev);
>> --
>> 1.9.1
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@...ts.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
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