Hi Thierry,
Am Dienstag, den 03.02.2015, 14:30 +0100 schrieb Thierry Reding:
On Thu, Dec 11, 2014 at 06:32:44PM +0100, Philipp Zabel wrote:
Many panel data sheets additionally to typical values list allowed ranges for timings such as hsync/vsync lengths, porches, and the pixel clock rate. These can be stored in a struct display_timing, to be used by an encoder mode_fixup callback to clamp user provided timing values or to validate workarounds for clock source limitations.
This patch adds a new drm_panel_funcs callback that returns the panels' available display_timing entries.
Signed-off-by: Philipp Zabel p.zabel@pengutronix.de
include/drm/drm_panel.h | 5 +++++ 1 file changed, 5 insertions(+)
Sorry for taking so long to get back on this. I generally like the idea, though a couple of things are unclear to me.
In struct display_timing we have:
struct timing_entry hactive; ... struct timing_entry vactive;
I wonder if that really makes sense. Are there really datasheets that provide a valid range for the number of horizontal and vertical active pixels?
I often see datasheets that give minimum, typical and maximum values also for the horizontal and vertical active pixels, but those are usually the same value. I don't know if there are any panels that really have documented ranges here.
[...]
@@ -68,6 +71,8 @@ struct drm_panel_funcs { int (*prepare)(struct drm_panel *panel); int (*enable)(struct drm_panel *panel); int (*get_modes)(struct drm_panel *panel);
- int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
struct display_timing *timings);Also are there even panels that support more than one set of timings? I've never heard of panels that are actually able to do more than one mode, so I'm wondering if num_timings isn't overdoing it a little here. I guess it doesn't hurt all that much, though.
I have not seen any yet that reasonably should be driven by the simple-panel driver. I was thinking about the Pixel Qi panel, but it turns out those just have a single timing and use the subpixels in B/W reflective mode.
regards Philipp