[PATCH v11 2/4] drm: Add API for capturing frame CRCs

[Emil Velikov]

On 6 October 2016 at 16:21, Tomeu Vizoso <tomeu.vizoso at collabora.com> wrote:
> Adds files and directories to debugfs for controlling and reading frame
> CRCs, per CRTC:
>
> dri/0/crtc-0/crc
> dri/0/crtc-0/crc/control
> dri/0/crtc-0/crc/data
>
> Drivers can implement the set_crc_source callback() in drm_crtc_funcs to
> start and stop generating frame CRCs and can add entries to the output
> by calling drm_crtc_add_crc_entry.
>
> v2:
>     - Lots of good fixes suggested by Thierry.
>     - Added documentation.
>     - Changed the debugfs layout.
>     - Moved to allocate the entries circular queue once when frame
>       generation gets enabled for the first time.
> v3:
>     - Use the control file just to select the source, and start and stop
>       capture when the data file is opened and closed, respectively.
>     - Make variable the number of CRC values per entry, per source.
>     - Allocate entries queue each time we start capturing as now there
>       isn't a fixed number of CRC values per entry.
>     - Store the frame counter in the data file as a 8-digit hex number.
>     - For sources that cannot provide useful frame numbers, place
>       XXXXXXXX in the frame field.
>
> v4:
>     - Build only if CONFIG_DEBUG_FS is enabled.
>     - Use memdup_user_nul.
>     - Consolidate calculation of the size of an entry in a helper.
>     - Add 0x prefix to hex numbers in the data file.
>     - Remove unnecessary snprintf and strlen usage in read callback.
>
> v5:
>     - Made the crcs array in drm_crtc_crc_entry fixed-size
>     - Lots of other smaller improvements suggested by Emil Velikov
>
> v7:
>     - Move definition of drm_debugfs_crtc_crc_add to drm_internal.h
>
> v8:
>     - Call debugfs_remove_recursive when we fail to create the minor
>       device
>
> v9:
>     - Register the debugfs directory for a crtc from
>       drm_crtc_register_all()
>
> v10:
>     - Don't let debugfs failures interrupt CRTC registration (Emil
>       Velikov)
>
> v11:
>     - Remove extra brace that broke compilation. Sorry!
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso at collabora.com>

Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

Emil