Re: [PATCH v4 3/3] drm/i915: New drm crtc property for varying the size of borders

Akash Goel
2014-04-11T03:02:53Z

On Thu, 2014-04-10 at 14:34 +0300, Ville Syrjälä wrote:
> On Thu, Apr 10, 2014 at 01:13:56PM +0530, Akash Goel wrote:
> > On Tue, 2014-04-08 at 19:28 +0300, Ville Syrjälä wrote:
> > > On Wed, Mar 26, 2014 at 09:25:12AM +0530, akash.goel@intel.com wrote:
> > > > From: Akash Goel <akash.goel@intel.com>
> > > >
> > > > This patch adds a new drm crtc property for varying the size of
> > > > the horizontal & vertical borers of the output/display window.
> > > > This will control the output of Panel fitter.
> > > >
> > > > v2: Added a new check for the invalid border size input
> > > >
> > > > v3: Fixed bugs in output window calculation
> > > > Removed superfluous checks
> > > >
> > > > v4: Added the capability to forecfully enable the Panel fitter.
> > > > The property value is of 64 bits, first 32 bits are used for
> > > > border dimensions. The 33rd bit can be used to forcefully
> > > > enable the panel fitter. This is useful for Panels which
> > > > do not override the User specified Pipe timings.
> > > >
> > > > Testcase: igt/kms_panel_fitter_test
> > > >
> > > > Signed-off-by: Akash Goel <akash.goel@intel.com>
> > > > ---
> > > > drivers/gpu/drm/i915/i915_drv.h | 7 ++
> > > > drivers/gpu/drm/i915/intel_display.c | 39 +++++++-
> > > > drivers/gpu/drm/i915/intel_drv.h | 5 +
> > > > drivers/gpu/drm/i915/intel_panel.c | 176 ++++++++++++++++++++++++++++++++---
> > > > 4 files changed, 211 insertions(+), 16 deletions(-)
> > > >
> <snip>
> > > > @@ -42,6 +57,60 @@ intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
> > > > drm_mode_set_crtcinfo(adjusted_mode, 0);
> > > > }
> > > >
> > > > +void
> > > > +intel_pch_manual_panel_fitting(struct intel_crtc *intel_crtc,
> > > > + struct intel_crtc_config *pipe_config)
> > > > +{
> > > > + struct drm_display_mode *adjusted_mode;
> > > > + int x, y;
> > > > + u32 pf_horizontal_ratio, pf_vertical_ratio;
> > > > + u32 tot_width, tot_height;
> > > > + u32 src_width, src_height; /* pipesrc.x, pipesrc.y */
> > > > + u32 dst_width, dst_height;
> > > > +
> > > > + adjusted_mode = &pipe_config->adjusted_mode;
> > > > +
> > > > + src_width = pipe_config->pipe_src_w;
> > > > + src_height = pipe_config->pipe_src_h;
> > > > +
> > > > + tot_width = adjusted_mode->hdisplay;
> > > > + tot_height = adjusted_mode->vdisplay;
> > > > +
> > > > + /*
> > > > + * Having non zero borders will reduce the size of 'HACTIVE/VACTIVE'
> > > > + * region. So (HACTIVE - Left border - Right Border) *
> > > > + * (VACTIVE - Top Border - Bottom border) will effectively be the
> > > > + * output rectangle on screen
> > > > + */
> > > > + dst_width = tot_width -
> > > > + (((intel_crtc->border_size >> 16) & 0xffff) * 2);
> > > > + dst_height = tot_height -
> > > > + ((intel_crtc->border_size & 0xffff) * 2);
> > >
> > > I'm thinking that we should allow the user to specify each border width
> > > individually rather than just assume left==right and top==bottom.
> > >
> >
> > Sorry I thought that the Top/Bottom & left/Right borders would be
> > symmetric only.
>
> I don't see a reason to limit ourselves here.
>

Fine, will extend this property to set each border separately.
Can I use the 12 bits for each border value, as that shall be
sufficient.

> > Tried setting the borders on EDP & HDMI panels by manipulating the Pipe
> > timings (through the logic used in 'centre_horizontally' &
> > 'centre_vertically' functions), but it didn't work.
> > Is this logic effective for the LVDS panel only ?
>
> Could be. Certainly the border enable bit is there only for LVDS. The
> gmch panel fitter isn't very flexible so it's possible we can't
> actually make it do many of the things the pch pfit can do.
>

Yes the GMCH panel fitter function is not equally capable as the PCH
counterpart. Here except the LVDS panel, it seems that borders cannot be
realized on any other panel, just via the manipulation of Pipe timings
(the way it can be done in PCH one).
For the same reason the 'Center' Panel fitting mode of "scaling mode"
property is not working on VLV (at least for HDMI/EDP panels).

> What happens if we set up the pfit to use manual scaling ratios but
> configure both scaling ratios so that scaled image won't fill the
> active video region in either direction? Does it position the scaled
> image at coordinates 0,0 and simply scan black the rest of the time after
> it's run out of source pixel data? Or does it automagically center the
> image and scan black on both sides? Or does it fail in some way?
>

Already tried that, but in vain. As per the VLV spec, the support for
Manual scaling ratio mode itself has been de-featured, so it didn't work
at all. So Auto/LetterBox/PillarBox modes are being supported.

As a next step tried to manipulate the Pipe timings, so as to produce
the borders on 4 sides of the panel. Similar to the PCH panel fitting
logic, kept the HSYNC/VSYNC pulse width same as well as the size of
HBLANK/VBLANK intervals, just manipulated the HYSNC/VSYNC and
HBLANK/VBLANK start & end points to create borders around the active
region.

Tried to add Left/Right borders of 32 columns and Top/bottom borders of
30 lines.
For that
HACTIVE=1920, HBLANK START=1920, HSYNC START=1968, HYSNC END=2000,
HBLANK END=2080, HTOTAL=2080.
was changed to
HACTIVE=1856, HBLANK START=1888, HSYNC START=1952, HYSNC END=1984,
HBLANK END=2048, HTOTAL=2080.

And Similarly
VACTIVE=1200, VBLANK START=1200, VSYNC START=1203, VYSNC END=1209,
VBLANK END=1235, VTOTAL=1235.
was changed to
VACTIVE=1140, VBLANK START=1170, VSYNC START=1185, VYSNC END=1191,
VBLANK END=1205, VTOTAL=1235.

After this manipulation, saw that the HMDI panel turned blank and showed
a "No Signal" message.
But for the same experiment, observed a different behavior with EDP
panel, that the display was active but the image was being shown in the
Top left part of the screen only, with the area outside active rectangle
having all junk data.

> >
> > > > +
> > > > + if ((dst_width == 0) || (dst_height == 0)) {
> > > > + DRM_ERROR("Invalid border size input\n");
> > > > + return;
> > >
> > > This is clear sign here that we should do all this stuff in the compute
> > > config stage so that we can fail gracefully and tell userspace that things
> > > didn't work out.
> > >
> >
> > Actually this call to decide the panel fitter config, is being made in
> > the context of 'compute config' only. But it's originating from the
> > 'crtc set property' & not from the modeset.
>
> We need to check things in both cases, and return an error if things
> can't work out.
>

Can this be done in a next patch set i.e. adding return types to the functions
so that if there is an error in panel fitter configuration, it can be communicated
back to User space.

> > Do you mean to say that if done from the 'modeset' call, we can report
> > back the error to User space for an invalid border setting.
> > Actually currently the return type is 'void' only for the 2 existing
> > panel fitter config functions.
> > Also we don't have a check in place for the max supported upscaling
> > ratio.
>
> Is there an upscaling limit? I know there's a downscaling limit of IIRC
> 1.125x or something close to that. I don't think we check that either.
>
Sorry my mistake, it's only the downscaling ratio which has a max value
of 1.125 i.e. PIPESRC cannot be downscaled by more than a factor of
1.125.

> >
> > > > + }
> > > > +
> > > > + pf_horizontal_ratio = panel_fitter_scaling(src_width, dst_width);
> > > > + pf_vertical_ratio = panel_fitter_scaling(src_height, dst_height);
> > > > +
> > > > + if (pf_horizontal_ratio > MAX_DOWNSCALE_RATIO) {
> > > > + DRM_ERROR("width is too small\n");
> > > > + return;
> > > > + } else if (pf_vertical_ratio > MAX_DOWNSCALE_RATIO) {
> > > > + DRM_ERROR("height is too small\n");
> > > > + return;
> > > > + }
> > > > +
> > > > + x = (adjusted_mode->hdisplay - dst_width + 1)/2;
> > > > + y = (adjusted_mode->vdisplay - dst_height + 1)/2;
> > > > +
> > > > + pipe_config->pch_pfit.pos = (x << 16) | y;
> > > > + pipe_config->pch_pfit.size = (dst_width << 16) | dst_height;
> > > > + pipe_config->pch_pfit.enabled = pipe_config->pch_pfit.size != 0;
> > > > +}
> > > > +
> > > > /* adjusted_mode has been preset to be the panel's fixed mode */
> > > > void
> > > > intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
> > > > @@ -55,6 +124,13 @@ intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
> > > >
> > > > x = y = width = height = 0;
> > > >
> > > > + /* check if User wants to apply the borders, or wants to forcefully
> > > > + enable the panel fitter, otherwise fall through the regular path */
> > > > + if (intel_crtc->pfit_enabled ||
> > > > + intel_crtc->border_size)
> > > > + return intel_pch_manual_panel_fitting(intel_crtc,
> > > > + pipe_config);
> > > > +
> > > > /* Native modes don't need fitting */
> > > > if (adjusted_mode->hdisplay == pipe_config->pipe_src_w &&
> > > > adjusted_mode->vdisplay == pipe_config->pipe_src_h)
> > > > @@ -157,19 +233,6 @@ centre_vertically(struct drm_display_mode *mode,
> > > > mode->crtc_vsync_end = mode->crtc_vsync_start + sync_width;
> > > > }
> > > >
> > > > -static inline u32 panel_fitter_scaling(u32 source, u32 target)
> > > > -{
> > > > - /*
> > > > - * Floating point operation is not supported. So the FACTOR
> > > > - * is defined, which can avoid the floating point computation
> > > > - * when calculating the panel ratio.
> > > > - */
> > > > -#define ACCURACY 12
> > > > -#define FACTOR (1 << ACCURACY)
> > > > - u32 ratio = source * FACTOR / target;
> > > > - return (FACTOR * ratio + FACTOR/2) / FACTOR;
> > > > -}
> > > > -
> > > > static void i965_scale_aspect(struct intel_crtc_config *pipe_config,
> > > > u32 *pfit_control)
> > > > {
> > > > @@ -247,6 +310,86 @@ static void i9xx_scale_aspect(struct intel_crtc_config *pipe_config,
> > > > }
> > > > }
> > > >
> > > > +void intel_gmch_manual_panel_fitting(struct intel_crtc *intel_crtc,
> > > > + struct intel_crtc_config *pipe_config)
> > > > +{
> > > > + struct drm_device *dev = intel_crtc->base.dev;
> > > > + u32 pfit_control = 0, border = 0;
> > > > + u32 pf_horizontal_ratio, pf_vertical_ratio;
> > > > + struct drm_display_mode *adjusted_mode;
> > > > + u32 tot_width, tot_height;
> > > > + u32 src_width, src_height; /* pipesrc.x, pipesrc.y */
> > > > + u32 dst_width, dst_height;
> > > > +
> > > > + adjusted_mode = &pipe_config->adjusted_mode;
> > > > +
> > > > + src_width = pipe_config->pipe_src_w;
> > > > + src_height = pipe_config->pipe_src_h;
> > > > +
> > > > + tot_width = adjusted_mode->hdisplay;
> > > > + tot_height = adjusted_mode->vdisplay;
> > > > +
> > > > + /*
> > > > + * Having non zero borders will reduce the size of 'HACTIVE/VACTIVE'
> > > > + * region. So (HACTIVE - Left border - Right Border) *
> > > > + * (VACTIVE - Top Border - Bottom border) will effectively be the
> > > > + * output rectangle on screen
> > > > + */
> > > > + dst_width = tot_width -
> > > > + (((intel_crtc->border_size >> 16) & 0xffff) * 2);
> > > > + dst_height = tot_height -
> > > > + ((intel_crtc->border_size & 0xffff) * 2);
> > > > +
> > > > + if ((dst_width == 0) || (dst_height == 0)) {
> > > > + DRM_ERROR("Invalid border size input\n");
> > > > + return;
> > > > + }
> > > > +
> > > > + pf_horizontal_ratio = panel_fitter_scaling(src_width, dst_width);
> > > > + pf_vertical_ratio = panel_fitter_scaling(src_height, dst_height);
> > > > +
> > > > + if (pf_horizontal_ratio > MAX_DOWNSCALE_RATIO) {
> > > > + DRM_ERROR("width is too small\n");
> > > > + return;
> > > > + } else if (pf_vertical_ratio > MAX_DOWNSCALE_RATIO) {
> > > > + DRM_ERROR("height is too small\n");
> > > > + return;
> > > > + }
> > > > +
> > > > + if (dst_width != tot_width)
> > > > + centre_horizontally(adjusted_mode, dst_width);
> > > > + if (dst_height != tot_height)
> > > > + centre_vertically(adjusted_mode, dst_height);
> > > > +
> > > > + /* No scaling needed now, but still enable the panel fitter,
> > > > + as that will allow the User to subequently do the dynamic
> > > > + flipping of fbs of different resolutions */
> > > > + if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
> > > > + adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h) {
> > > > + BUG_ON(!intel_crtc->pfit_enabled);
> > > > + DRM_DEBUG_KMS("Forcefully enabling the Panel fitter\n");
> > > > + }
> > > > +
> > > > + border = LVDS_BORDER_ENABLE;
> > > > +
> > > > + if (INTEL_INFO(dev)->gen >= 4) {
> > > > + /* PFIT_SCALING_PROGRAMMED is de-featured on BYT */
> > > > + pfit_control |= PFIT_ENABLE | PFIT_SCALING_AUTO;
> > > > + pfit_control |= ((intel_crtc->pipe << PFIT_PIPE_SHIFT) | PFIT_FILTER_FUZZY);
> > > > + } else {
> > > > + pfit_control |= (PFIT_ENABLE |
> > > > + VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
> > > > + VERT_INTERP_BILINEAR | HORIZ_INTERP_BILINEAR);
> > > > + }
> > > > +
> > > > + /* Make sure pre-965 set dither correctly for 18bpp panels. */
> > > > + if (INTEL_INFO(dev)->gen < 4 && pipe_config->pipe_bpp == 18)
> > > > + pfit_control |= PANEL_8TO6_DITHER_ENABLE;
> > > > +
> > > > + pipe_config->gmch_pfit.control = pfit_control;
> > > > + pipe_config->gmch_pfit.lvds_border_bits = border;
> > > > +}
> > > > +
> > > > void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
> > > > struct intel_crtc_config *pipe_config,
> > > > int fitting_mode)
> > > > @@ -257,6 +400,13 @@ void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
> > > >
> > > > adjusted_mode = &pipe_config->adjusted_mode;
> > > >
> > > > + /* check if User wants to apply the borders, or wants to forcefully
> > > > + enable the panel fitter, otherwise fall through the regular path */
> > > > + if (intel_crtc->pfit_enabled ||
> > > > + intel_crtc->border_size)
> > > > + return intel_gmch_manual_panel_fitting(intel_crtc,
> > > > + pipe_config);
> > > > +
> > > > /* Native modes don't need fitting */
> > > > if (adjusted_mode->hdisplay == pipe_config->pipe_src_w &&
> > > > adjusted_mode->vdisplay == pipe_config->pipe_src_h)
> > > > --
> > > > 1.8.5.2
> > > >
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > >
> >
>

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