[Intel-gfx] [PATCH v2 2/3] drm: Create a format/modifier blob
Emil Velikov
emil.l.velikov at gmail.com
Thu May 18 09:49:01 UTC 2017
On 18 May 2017 at 01:46, Ben Widawsky <ben at bwidawsk.net> wrote:
>>> + blob_size += modifiers_size;
>>> +
>>> + blob = drm_property_create_blob(dev, blob_size, NULL);
>>> + if (IS_ERR(blob))
>>> + return -1;
>>> +
>>
>> Maybe propagate the exact error... Hmm we don't seem to check if
>> create_in_format_blob fails either so perhaps it's not worth it.
>>
>>
>
> In this case it's almost definitely ENOMEM. All values should be verified -
> I
> think the other errors are there for when userspace is utilizing blob
> creation.
>
> So I'll just leave it.
>
Ack, sure thing.
>>> --- a/include/uapi/drm/drm_mode.h
>>> +++ b/include/uapi/drm/drm_mode.h
>>> @@ -665,6 +665,56 @@ struct drm_mode_atomic {
>>> __u64 user_data;
>>> };
>>>
>>> +struct drm_format_modifier_blob {
>>> +#define FORMAT_BLOB_CURRENT 1
>>> + /* Version of this blob format */
>>> + u32 version;
>>> +
>>> + /* Flags */
>>> + u32 flags;
>>> +
>>> + /* Number of fourcc formats supported */
>>> + u32 count_formats;
>>> +
>>> + /* Where in this blob the formats exist (in bytes) */
>>> + u32 formats_offset;
>>> +
>>> + /* Number of drm_format_modifiers */
>>> + u32 count_modifiers;
>>> +
>>> + /* Where in this blob the modifiers exist (in bytes) */
>>> + u32 modifiers_offset;
>>> +
>>> + /* u32 formats[] */
>>> + /* struct drm_format_modifier modifiers[] */
>>> +};
>>> +
>>> +struct drm_format_modifier {
>>> + /* Bitmask of formats in get_plane format list this info applies
>>> to. The
>>> + * offset allows a sliding window of which 64 formats (bits).
>>> + *
>>> + * Some examples:
>>> + * In today's world with < 65 formats, and formats 0, and 2 are
>>> + * supported
>>> + * 0x0000000000000005
>>> + * ^-offset = 0, formats = 5
>>> + *
>>> + * If the number formats grew to 128, and formats 98-102 are
>>> + * supported with the modifier:
>
> G>> + *
>>>
>>> + * 0x0000003c00000000 0000000000000000
>>> + * ^
>>> + * |__offset = 64, formats = 0x3c00000000
>>> + *
>>> + */
>>> + __u64 formats;
>>> + __u32 offset;
>>> + __u32 pad;
>>> +
>>> + /* The modifier that applies to the >get_plane format list
>>> bitmask. */
>>> + __u64 modifier;
>>
>> Please drop the leading __ from the type names in UAPI headers.
>>
>
> Many other structures have the __, can you explain why please (this has
> probably
> been beaten to death already; but I don't know)?
>
Got confused there for a moment, apologies.
Using the __ types is correct. It is drm_format_modifier_blob that
should be updated to follow suit.
-Emil
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