On Wed, Apr 10, 2019 at 01:20:44PM +0000, Shankar, Uma wrote: > > > >-----Original Message----- > >From: dri-devel [mailto:dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Ville > >Syrjälä > >Sent: Monday, April 8, 2019 9:38 PM > >To: Shankar, Uma <uma.shankar@xxxxxxxxx> > >Cc: dcastagna@xxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; dri- > >devel@xxxxxxxxxxxxxxxxxxxxx; seanpaul@xxxxxxxxxxxx; Syrjala, Ville > ><ville.syrjala@xxxxxxxxx>; Lankhorst, Maarten <maarten.lankhorst@xxxxxxxxx> > >Subject: Re: [v2 0/7] Add Multi Segment Gamma Support > > > >On Mon, Apr 08, 2019 at 03:59:51PM +0000, Shankar, Uma wrote: > >> > >> > >> >-----Original Message----- > >> >From: dri-devel [mailto:dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx] On > >> >Behalf Of Ville Syrjälä > >> >Sent: Monday, April 8, 2019 9:15 PM > >> >To: Shankar, Uma <uma.shankar@xxxxxxxxx> > >> >Cc: dcastagna@xxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; dri- > >> >devel@xxxxxxxxxxxxxxxxxxxxx; seanpaul@xxxxxxxxxxxx; Syrjala, Ville > >> ><ville.syrjala@xxxxxxxxx>; Lankhorst, Maarten > >> ><maarten.lankhorst@xxxxxxxxx> > >> >Subject: Re: [v2 0/7] Add Multi Segment Gamma Support > >> > > >> >On Mon, Apr 08, 2019 at 03:40:39PM +0000, Shankar, Uma wrote: > >> >> > >> >> > >> >> >-----Original Message----- > >> >> >From: Ville Syrjälä [mailto:ville.syrjala@xxxxxxxxxxxxxxx] > >> >> >Sent: Monday, April 8, 2019 8:27 PM > >> >> >To: Shankar, Uma <uma.shankar@xxxxxxxxx> > >> >> >Cc: dcastagna@xxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; dri- > >> >> >devel@xxxxxxxxxxxxxxxxxxxxx; seanpaul@xxxxxxxxxxxx; Syrjala, Ville > >> >> ><ville.syrjala@xxxxxxxxx>; Lankhorst, Maarten > >> >> ><maarten.lankhorst@xxxxxxxxx> > >> >> >Subject: Re: [v2 0/7] Add Multi Segment Gamma Support > >> >> > > >> >> >On Mon, Apr 08, 2019 at 02:40:51PM +0000, Shankar, Uma wrote: > >> >> >> > >> >> >> > >> >> >> >-----Original Message----- > >> >> >> >From: Ville Syrjälä [mailto:ville.syrjala@xxxxxxxxxxxxxxx] > >> >> >> >Sent: Monday, April 8, 2019 6:01 PM > >> >> >> >To: Shankar, Uma <uma.shankar@xxxxxxxxx> > >> >> >> >Cc: dcastagna@xxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; > >> >> >> >dri- devel@xxxxxxxxxxxxxxxxxxxxx; seanpaul@xxxxxxxxxxxx; > >> >> >> >Syrjala, Ville <ville.syrjala@xxxxxxxxx>; Lankhorst, Maarten > >> >> >> ><maarten.lankhorst@xxxxxxxxx> > >> >> >> >Subject: Re: [v2 0/7] Add Multi Segment Gamma > >> >> >> >Support > >> >> >> > > >> >> >> >On Mon, Apr 08, 2019 at 12:26:23PM +0000, Shankar, Uma wrote: > >> >> >> >> > >> >> >> >> > >> >> >> >> >-----Original Message----- > >> >> >> >> >From: dri-devel > >> >> >> >> >[mailto:dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx] > >> >> >> >> >On Behalf Of Ville Syrjälä > >> >> >> >> >Sent: Friday, April 5, 2019 9:42 PM > >> >> >> >> >To: Shankar, Uma <uma.shankar@xxxxxxxxx> > >> >> >> >> >Cc: dcastagna@xxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; > >> >> >> >> >dri- devel@xxxxxxxxxxxxxxxxxxxxx; seanpaul@xxxxxxxxxxxx; > >> >> >> >> >Syrjala, Ville <ville.syrjala@xxxxxxxxx>; Lankhorst, Maarten > >> >> >> >> ><maarten.lankhorst@xxxxxxxxx> > >> >> >> >> >Subject: Re: [v2 0/7] Add Multi Segment Gamma > >> >> >> >> >Support > >> >> >> >> > > >> >> >> >> >On Mon, Apr 01, 2019 at 11:00:04PM +0530, Uma Shankar wrote: > >> >> >> >> >> This series adds support for programmable gamma modes and > >> >> >> >> >> exposes a property interface for the same. Also added, > >> >> >> >> >> support for multi segment gamma mode introduced in ICL+ > >> >> >> >> >> > >> >> >> >> >> It creates 2 property interfaces : > >> >> >> >> >> 1. GAMMA_MODE_CAPS: This is immutable property and exposes > >> >> >> >> >> the various gamma modes supported and the lut ranges. This > >> >> >> >> >> is an enum property with element as blob id. Getting the > >> >> >> >> >> blob id in userspace, user can get the mode supported and > >> >> >> >> >> also the range of gamma mode supported with number of lut > >coefficients. > >> >> >> >> >> > >> >> >> >> >> 2. GAMMA_MODE: This is for user to set the gamma mode and > >> >> >> >> >> send the lut values for that particular mode. > >> >> >> >> > > >> >> >> >> >I think we should just go for the BLOB_ENUM prop type instead. > >> >> >> >> >Then the possible values and the current value are all part of the same > >prop. > >> >> >> >> > >> >> >> >> Hi Ville, > >> >> >> >> With the current approach, we have enum property with values > >> >> >> >> as blob_ids (representing platform capabilities). This should > >> >> >> >> not get modified and needs to be immutable. > >> >> >> > > >> >> >> >That's not quite what we want. We want to let the user modify > >> >> >> >the current value so that they can actually select the gamma mode. > >> >> >> >Otherwise we need yet another prop for it, or we have to deduce > >> >> >> >it from the LUT size (that apporach would actually work for > >> >> >> >i915 but may not work for other drivers/hardware). > >> >> >> > > >> >> >> >> > >> >> >> >> Userspace can query the property and get the blob using the blob_ids. > >> >> >> >> Thereby getting all the platform capabilities. > >> >> >> >> > >> >> >> >> Now to set the LUT values, he can use another blob property > >> >> >> >> and pass the luts. This is inline to how gamma/degamma is > >> >> >> >> implemented where we have one immutable LUT_SIZE property > >> >> >> >> (indicating number of > >> >> >> >> luts) and another blob property for actual lut values.. > >> >> >> > >> >> >> Hi Ville, > >> >> >> Just to clarify and clear some doubts :) > >> >> >> > >> >> >> We should be able to set the gamma mode using the blob enum value. > >> >> >> Userspace will get the list enum vals (blob ids with mode name > >> >> >> embedded) and > >> >> >select one and do a setprop to set a mode. > >> >> >> Driver will get the blob_id and will be able to get the mode to > >> >> >> be set. So exposing capabilities and setting the mode should be > >> >> >> possible with this one > >> >> >property. I hope my understanding is correct. > >> >> >> > >> >> >> Now to send the actual blob values to be set, we need to use > >> >> >> some other property interface. Should we use the currently > >> >> >> available "gamma blob > >> >> >(gamma_lut_property)" property to send the lut values. > >> >> >> The challenge there is that it currently uses 16 bit lut values > >> >> >> struct drm_color_lut { > >> >> >> __u16 red; > >> >> >> __u16 green; > >> >> >> __u16 blue; > >> >> >> __u16 reserved; > >> >> >> }; > >> >> >> which is not sufficient for HDR usecases. Or should we need a > >> >> >> new property for > >> >> >advance lut/extended lut like below: > >> >> >> https://patchwork.freedesktop.org/patch/294732/?series=30875&rev > >> >> >> =7 > >> >> >> > >> >> >> What do you suggest ? > >> >> > > >> >> >I was thinking that we might get away with reusing the current > >> >> >props and just change the interpretation of the data when > >> >> >gamma_mode is set. But I'm not sure that's going to work out so > >> >> >well if one client sets this up and then another client comes > >> >> >along that doesn't understand the new props at all. But even with > >> >> >separate props I think we might still end up in a mess because the > >> >> >new client wouldn't know how to unset the higher precision LUT > >> >> >before setting up the old style prop and the > >> >kernel would then refuse the operation with with both props being set. > >> >> > > >> >> >So I think we might need a client cap for this which simply > >> >> >changes how the data in the existing props is represented. So > >> >> >internally we could always store things in the new high precision > >> >> >format, but we'd convert to/from the old format when dealing with an older > >client. > >> >> > >> >> We could also say that if a legacy gamma_mode_property is set > >> >> (which will be used by legacy apps or apps not aware of new > >> >> interface), in driver we will simply unset the earlier gamma_mode > >> >> and fallback to legacy mode (whatever it was for a particular > >> >> platform). This way we should be able to deal with this situation and an explicit > >unset may not be needed. > >> >What do you think ? > >> > > >> >I don't want (non-immutable) properties that magically change values. > >> >That way lies madness. > >> > >> Oh ok. So do you suggest that we add some kind of flag to be set by > >> user, based on which we take either legacy or advance_gamma path. Is my > >understanding correct ? > > > >Yeah, just another client cap. I can't immediately think of a nicer way to extend the > >precision. > > Sure Ville, I am implementing based on this suggestion. Basically will expose a new > advance_gamma_mode flag as a client cap. Something like: > > #define DRM_CLIENT_CAP_ADVANCE_GAMMA_MODES 6 > > The new users will set this and we will assume that advance gamma mode paths is active. > If the flag is not set, driver will take the legacy path and enable default gamma_mode for > that particular platform. It's maybe a still a bit nasty because we basically have to ignore the gamma mode prop entirely in that case. Not quite sure what is the best way to shoehorn this in. I guess the main problem is what we would report to userspace via the (DE)GAMMA_MODE props if the previous client left gamma_mode set in a way that conflicts with what (DE)GAMMA_LUT_SIZE suggests it should be. -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
