Re: [PATCH 09/12] drm: Shrink drm_display_mode timings

Ville Syrjälä
2020-02-24T13:06:05Z

On Fri, Feb 21, 2020 at 06:27:22PM +0100, Sam Ravnborg wrote:
> Hi Ville.
>
> On Wed, Feb 19, 2020 at 10:35:41PM +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Store the timings (apart from the clock) as u16. The uapi mode
> > struct already uses u16 for everything so using something bigger
> > internally doesn't really help us.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> While touchign this - have you cinsidered to put all the timing
> fields in a dedicated struct - and then have two instanses of said
> struct here?

The normal vs. crtc timigns aren't the same. But I've been pondering
about pulling the crtc timings into a separate struct and using that
in some places where we currently use a full drm_display_mode but only
really care about the crtc timings.

>
> Like:
>
> /**
> * struct panel_timing - timing configuratio for a panel
> *
> * The timing is in khz and ...
> /*
> struct panel_timing {
> /**
> * @clock: Panel clock in khz
> */
> int clock;
>
> /**
> * @hdisplay: bla bla
> */
> u16 hdisplay;
> u16 hsync_start;
> u16 hsync_end;
> u16 htotal;
> u16 hskew;
> u16 vdisplay;
> u16 vsync_start;
> u16 vsync_end;
> u16 vtotal;
> u16 vscan;
> };
>
>
> And then in drm_display_mode:
>
> /**
> * @hw_timing: The timing for the panel
> */
> struct panel_timing hw_timing;
>
> /**
> * @calc_timing: The calculated timing
> */
> struct panel_timing calc_timing;
>
> Or something like that.
> We could use the panel_timign struct in some other places I think.
>
> Sam
>
> > ---
> > drivers/gpu/drm/drm_modes.c | 7 ------
> > include/drm/drm_modes.h | 46 ++++++++++++++++++-------------------
> > 2 files changed, 23 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> > index 0e7c9ba241c4..cc9fc52f9f7c 100644
> > --- a/drivers/gpu/drm/drm_modes.c
> > +++ b/drivers/gpu/drm/drm_modes.c
> > @@ -1917,13 +1917,6 @@ EXPORT_SYMBOL(drm_mode_create_from_cmdline_mode);
> > void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out,
> > const struct drm_display_mode *in)
> > {
> > - WARN(in->hdisplay > USHRT_MAX || in->hsync_start > USHRT_MAX ||
> > - in->hsync_end > USHRT_MAX || in->htotal > USHRT_MAX ||
> > - in->hskew > USHRT_MAX || in->vdisplay > USHRT_MAX ||
> > - in->vsync_start > USHRT_MAX || in->vsync_end > USHRT_MAX ||
> > - in->vtotal > USHRT_MAX || in->vscan > USHRT_MAX,
> > - "timing values too large for mode info\n");
> > -
> > out->clock = in->clock;
> > out->hdisplay = in->hdisplay;
> > out->hsync_start = in->hsync_start;
> > diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> > index b28c0234fcd7..b585074945b5 100644
> > --- a/include/drm/drm_modes.h
> > +++ b/include/drm/drm_modes.h
> > @@ -278,16 +278,16 @@ struct drm_display_mode {
> > * Pixel clock in kHz.
> > */
> > int clock; /* in kHz */
> > - int hdisplay;
> > - int hsync_start;
> > - int hsync_end;
> > - int htotal;
> > - int hskew;
> > - int vdisplay;
> > - int vsync_start;
> > - int vsync_end;
> > - int vtotal;
> > - int vscan;
> > + u16 hdisplay;
> > + u16 hsync_start;
> > + u16 hsync_end;
> > + u16 htotal;
> > + u16 hskew;
> > + u16 vdisplay;
> > + u16 vsync_start;
> > + u16 vsync_end;
> > + u16 vtotal;
> > + u16 vscan;
> > /**
> > * @flags:
> > *
> > @@ -356,19 +356,19 @@ struct drm_display_mode {
> > * difference is exactly a factor of 10.
> > */
> > int crtc_clock;
> > - int crtc_hdisplay;
> > - int crtc_hblank_start;
> > - int crtc_hblank_end;
> > - int crtc_hsync_start;
> > - int crtc_hsync_end;
> > - int crtc_htotal;
> > - int crtc_hskew;
> > - int crtc_vdisplay;
> > - int crtc_vblank_start;
> > - int crtc_vblank_end;
> > - int crtc_vsync_start;
> > - int crtc_vsync_end;
> > - int crtc_vtotal;
> > + u16 crtc_hdisplay;
> > + u16 crtc_hblank_start;
> > + u16 crtc_hblank_end;
> > + u16 crtc_hsync_start;
> > + u16 crtc_hsync_end;
> > + u16 crtc_htotal;
> > + u16 crtc_hskew;
> > + u16 crtc_vdisplay;
> > + u16 crtc_vblank_start;
> > + u16 crtc_vblank_end;
> > + u16 crtc_vsync_start;
> > + u16 crtc_vsync_end;
> > + u16 crtc_vtotal;
> >
> > /**
> > * @private_flags:
> > --
> > 2.24.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Ville Syrjälä
Intel