Hi Thierry, å¨ 2015/8/25 18:06, Thierry Reding åé: > On Tue, Aug 25, 2015 at 05:41:19PM +0800, Yakir Yang wrote: >> Hi Thierry, >> >> å¨ 2015/8/25 17:12, Thierry Reding åé: >>> On Mon, Aug 24, 2015 at 09:48:27AM -0500, Rob Herring wrote: >>>> On Mon, Aug 24, 2015 at 7:57 AM, Russell King - ARM Linux >>>> <linux at arm.linux.org.uk> wrote: >>>>> On Sun, Aug 23, 2015 at 06:23:14PM -0500, Rob Herring wrote: >>>>>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk at rock-chips.com> >>>>>> wrote: >>>>>>> + -analogix,color-depth: >>>>>>> + number of bits per colour component. >>>>>>> + COLOR_6 = 0, COLOR_8 = 1, COLOR_10 = 2, >>>>>>> COLOR_12 = 3 >>>>>> This seems pretty generic. Just use 6, 8, 10, or 12 for values. And >>>>>> drop the vendor prefix. >>>>> Please think about this some more. What does "color-depth" mean? Does it >>>>> mean the number of bits per colour _component_, or does it mean the total >>>>> number of bits to represent a particular colour. It's confusing as it >>>>> stands. >>>> Then "component-color-bpp" perhaps? >>> There should be no need to have this in DT at all. The BPC is a property >>> of the attached panel and it should come from the panel (either the >>> panel driver or parsed from EDID if available). >> Actually I have send an email about this one to you in version 2, just past >> from that email: >> >> "samsung,color_space" and "samsung,color-depth" >> >> The drm_display_info's color_formats and bpc indicate the monitor display >> ability, but >> the edp driver could not take it as input video format directly. >> >> For example, with my DP TV I would found "RGB444 & YCRCB422 & & YCRCB444" >> support in drm_display_info.color_formats and 16bit bpc support, but RK3288 >> crtc >> driver could only output RGB & ITU formats, so finally analogix_dp-rockchip >> driver >> config crtc to RGBaaa 10bpc mode. >> >> In this sutiation, the analogix_dp core driver would pazzled by the >> drm_display_info, >> can't chose the right color_space and bpc. >> >> And this is the place that confused me, wish you could give some ideas about >> this one :-) > Your display driver should choose whatever it is capable of outputting. > If the display reports that it can do 16 bits-per-color, but your > display driver can't do it, then it should choose a configuration that > it supports. Similarily for the color encodings. If you can't generate > YCrCb444 with your hardware, then it's the driver's job to know about > that and select the next appropriate configuration. > > But hard-coding this is not the right solution because the value in DT > may end up conflicting with what the display reports.
Yeah, thanks for your explain, you are right. It's the best way to get "color-depth" and "color-space" from display driver, not to hard-code in DT prop. But if the common analogix-dp driver want to get those values, then those values should come from the common drm struct data. Personally I think "struct drm_crtc" is the best place that should indicate the output ability of SoC vop/lcdc. But I haven't find out there are some place to store those message for now (I don't think it's good to modify the original color-space and color-bpc which parsed from monitor edid). So could you share sme ideas about this, and I would rather to talk with Mark (Author of rockchip drm driver) to find out the better way to fix this one. Besides, I would appreciate very much if you can share some ideas about how Exynos handler with this problem ;) Thanks, - Yakir > Thierry
