Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Wed, 27 May 2020 09:34:30 +0200 | Subject | Re: [PATCH v5 0/8] drm: rcar-du: Add Color Management Module (CMM) |
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Hi Eugeniu,
On Wed, May 27, 2020 at 9:16 AM Eugeniu Rosca <erosca@de.adit-jv.com> wrote: > On Tue, Oct 15, 2019 at 12:46:13PM +0200, Jacopo Mondi wrote: > > CMM functionalities are retained between suspend/resume cycles (tested with > > suspend-to-idle) without requiring a re-programming of the LUT tables. > > Hmm. Is this backed up by any statement in the HW User's manual? > This comes in contrast with the original Renesas CMM implementation [**] > which does make use of suspend (where the freeze actually happens). > > Can we infer, based on your statement, that we could also get rid of > the suspend callback in [**]?
While the CMM state will be retained across suspend-to-idle, I'm quite sure it will be lost by suspend-to-RAM, at least on the Salvator-X(S), ULCB, and Ebisu development boards, as PSCI will ask the BD9571WMV regulator to power down the R-Car SoC.
So IMHO we do need suspend/resume handling.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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