On 03/11/2014 05:24 PM, Laurent Pinchart wrote:
> Hi Hans,
>
> On Tuesday 11 March 2014 17:11:07 Hans Verkuil wrote:
>> On 03/11/2014 05:08 PM, Laurent Pinchart wrote:
>>> Hi Hans,
>>>
>>> On Tuesday 11 March 2014 16:44:27 Hans Verkuil wrote:
>>>> On 03/11/2014 04:09 PM, Laurent Pinchart wrote:
>>>>> The subdev EDID ioctls receive a pad field that must reference an
>>>>> existing pad and an EDID field that must point to a buffer. Validate
>>>>> both fields in the core code instead of duplicating validation in all
>>>>> drivers.
>>>>>
>>>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>>>>> Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
>>>>
>>>> Here is my:
>>>>
>>>> Reviewed-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>>>
>>>> But take note: the adv7604 driver does not handle a get_edid with
>>>> edid->blocks == 0 correctly: it should fill in the blocks field with the
>>>> real number of blocks and return 0 instead of returning EINVAL.
>>>
>>> Should it also set edid->start_block to 0 ?
>>
>> I don't think so. It makes sense to just set blocks to the total number of
>> available blocks - edid->start_block.
>
> OK.
>
>> Note that if edid->start_block >= total number of EDID blocks, then -ENODATA
>> should be returned.
>
> What if S_EDID hasn't been called yet ? Should the driver set edid->blocks to
> 0 and return success ? Or should it return -ENODATA ?
If start_block == 0 and blocks == 0, then return 0. If start_block > 0, then you
attempt to read a block that doesn't exist, so -ENODATA should be returned.
> There's quite a few possible combinations, we should probably start by
> clarifying the spec.
>
It's easier to code:
if (tot_blocks == 0) {
/* Referring to blocks we don't have? Return -ENODATA! */
if (edid->start_block || edid->blocks)
return -ENODATA;
/* We have 0 blocks starting at block 0, so that's perfectly
fine! */
return 0;
}
if (edid->start_block >= tot_blocks)
return -ENODATA;
if (edid->blocks == 0) {
edid->blocks = tot_blocks - edid->start_block;
return 0;
}
if (tot_blocks - edid->start_block < edid->blocks)
edid->blocks = tot_blocks - edid->start_block;
/* copy edid->blocks from start_block to edid->edid */
return 0;
Regards,
Hans
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