On Tue, Jan 22, 2019 at 07:22:24PM +0200, Imre Deak wrote:
> On Mon, Nov 12, 2018 at 06:59:58PM +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrj...@linux.intel.com>
> >
> > To make vblank timestamps work better with the TV encoder let's
> > scale the pipe timings such that the relationship between the
> > TV active and TV blanking periods is mirrored in the
> > corresponding pipe timings.
> >
> > Note that in reality the pipe runs at a faster speed during the
> > TV vblank, and correspondigly there are periods when the pipe
> > is enitrely stopped. We pretend that this isn't the case and
> > as such we incur some error in the vblank timestamps during
> > the TV vblank. Further explanation of the issues in a big
> > comment in the code.
> >
> > This makes the vblank timestamps good enough to make
> > i965gm (which doesn't have a working frame counter with
> > the TV encoder) report correct frame numbers. Previously
> > you could get all kinds of nonsense which resulted in
> > eg. glxgears reporting that it's running at twice the
> > actual framerate in most cases.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/i915_reg.h | 1 +
> > drivers/gpu/drm/i915/intel_tv.c | 322 +++++++++++++++++++++++++++-----
> > 2 files changed, 278 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h
> > b/drivers/gpu/drm/i915/i915_reg.h
> > index fe4b913e46ac..10813ae7bee7 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -4848,6 +4848,7 @@ enum {
> > # define TV_OVERSAMPLE_NONE (2 << 18)
> > /* Selects 8x oversampling */
> > # define TV_OVERSAMPLE_8X (3 << 18)
> > +# define TV_OVERSAMPLE_MASK (3 << 18)
> > /* Selects progressive mode rather than interlaced */
> > # define TV_PROGRESSIVE (1 << 17)
> > /* Sets the colorburst to PAL mode. Required for non-M PAL modes. */
> > diff --git a/drivers/gpu/drm/i915/intel_tv.c
> > b/drivers/gpu/drm/i915/intel_tv.c
> > index 216525dd144a..75126fce655d 100644
> > --- a/drivers/gpu/drm/i915/intel_tv.c
> > +++ b/drivers/gpu/drm/i915/intel_tv.c
> > @@ -340,7 +340,6 @@ struct tv_mode {
> > const struct video_levels *composite_levels, *svideo_levels;
> > const struct color_conversion *composite_color, *svideo_color;
> > const u32 *filter_table;
> > - u16 max_srcw;
> > };
> >
> >
> > @@ -729,7 +728,6 @@ static const struct tv_mode tv_modes[] = {
> > .burst_ena = false,
> >
> > .filter_table = filter_table,
> > - .max_srcw = 800
> > },
> > {
> > .name = "1080i@50Hz",
> > @@ -947,13 +945,183 @@ intel_tv_mode_vdisplay(const struct tv_mode *tv_mode)
> > return 2 * (tv_mode->nbr_end + 1);
> > }
> >
> > +static void
> > +intel_tv_mode_to_mode(struct drm_display_mode *mode,
> > + const struct tv_mode *tv_mode)
> > +{
> > + mode->clock = tv_mode->clock /
> > + (tv_mode->oversample >> !tv_mode->progressive);
> > +
> > + /*
> > + * tv_mode horizontal timings:
> > + *
> > + * hsync_end
> > + * | hblank_end
> > + * | | hblank_start
> > + * | | | htotal
> > + * | _______ |
> > + * ____/ \___
> > + * \__/ \
> > + */
> > + mode->hdisplay =
> > + tv_mode->hblank_start - tv_mode->hblank_end;
> > + mode->hsync_start = mode->hdisplay +
> > + tv_mode->htotal - tv_mode->hblank_start;
> > + mode->hsync_end = mode->hsync_start +
> > + tv_mode->hsync_end;
> > + mode->htotal = tv_mode->htotal + 1;
> > +
> > + /*
> > + * tv_mode vertical timings:
> > + *
> > + * vsync_start
> > + * | vsync_end
> > + * | | vi_end nbr_end
> > + * | | | |
> > + * | | _______
> > + * \__ ____/ \
> > + * \__/
> > + */
> > + mode->vdisplay = intel_tv_mode_vdisplay(tv_mode);
> > + if (tv_mode->progressive) {
> > + mode->vsync_start = mode->vdisplay +
> > + tv_mode->vsync_start_f1 + 1;
> > + mode->vsync_end = mode->vsync_start +
> > + tv_mode->vsync_len;
> > + mode->vtotal = mode->vdisplay +
> > + tv_mode->vi_end_f1 + 1;
> > + } else {
> > + mode->vsync_start = mode->vdisplay +
> > + tv_mode->vsync_start_f1 + 1 +
> > + tv_mode->vsync_start_f2 + 1;
> > + mode->vsync_end = mode->vsync_start +
> > + 2 * tv_mode->vsync_len;
> > + mode->vtotal = mode->vdisplay +
> > + tv_mode->vi_end_f1 + 1 +
> > + tv_mode->vi_end_f2 + 1;
> > + }
> > +
> > + /* TV has it's own notion of sync and other mode flags, so clear them.
> > */
> > + mode->flags = 0;
> > +
> > + mode->vrefresh = 0;
>
> Redundant line.
drm_mode_vrefresh() won't recompute the value if it's already
set. So unless we clear it first this would effectively become
'mode->vrefresh = mode->vrefresh'.
The whole mode->vrefesh story is a bit sad, and someone should
really rework how it all works.
>
> > + mode->vrefresh = drm_mode_vrefresh(mode);
> > +
> > + snprintf(mode->name, sizeof(mode->name),
> > + "%dx%d%c (%s)",
> > + mode->hdisplay, mode->vdisplay,
> > + tv_mode->progressive ? 'p' : 'i',
> > + tv_mode->name);
> > +}
> > +
> > +static void intel_tv_scale_mode_horiz(struct drm_display_mode *mode,
> > + int hdisplay, int left_margin,
> > + int right_margin)
> > +{
> > + int hsync_start = mode->hsync_start - mode->hdisplay + right_margin;
> > + int hsync_end = mode->hsync_end - mode->hdisplay + right_margin;
> > + int new_htotal = mode->htotal * hdisplay /
> > + (mode->hdisplay - left_margin - right_margin);
> > +
> > + mode->clock = mode->clock * new_htotal / mode->htotal;
> > +
> > + mode->hdisplay = hdisplay;
> > + mode->hsync_start = hdisplay + hsync_start * new_htotal / mode->htotal;
> > + mode->hsync_end = hdisplay + hsync_end * new_htotal / mode->htotal;
> > + mode->htotal = new_htotal;
> > +}
> > +
> > +static void intel_tv_scale_mode_vert(struct drm_display_mode *mode,
> > + int vdisplay, int top_margin,
> > + int bottom_margin)
> > +{
> > + int vsync_start = mode->vsync_start - mode->vdisplay + bottom_margin;
> > + int vsync_end = mode->vsync_end - mode->vdisplay + bottom_margin;
> > + int new_vtotal = mode->vtotal * vdisplay /
> > + (mode->vdisplay - top_margin - bottom_margin);
> > +
> > + mode->clock = mode->clock * new_vtotal / mode->vtotal;
> > +
> > + mode->vdisplay = vdisplay;
> > + mode->vsync_start = vdisplay + vsync_start * new_vtotal / mode->vtotal;
> > + mode->vsync_end = vdisplay + vsync_end * new_vtotal / mode->vtotal;
> > + mode->vtotal = new_vtotal;
> > +}
> > +
> > static void
> > intel_tv_get_config(struct intel_encoder *encoder,
> > struct intel_crtc_state *pipe_config)
> > {
> > + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > + struct drm_display_mode *adjusted_mode =
> > + &pipe_config->base.adjusted_mode;
> > + struct drm_display_mode mode = {};
> > + u32 tv_ctl, hctl1, hctl3, vctl1, vctl2, tmp;
> > + struct tv_mode tv_mode = {};
> > + int hdisplay = adjusted_mode->crtc_hdisplay;
> > + int vdisplay = adjusted_mode->crtc_vdisplay;
> > + int xsize, ysize, xpos, ypos;
> > +
> > pipe_config->output_types |= BIT(INTEL_OUTPUT_TVOUT);
> >
> > - pipe_config->base.adjusted_mode.crtc_clock = pipe_config->port_clock;
> > + tv_ctl = I915_READ(TV_CTL);
> > + hctl1 = I915_READ(TV_H_CTL_1);
> > + hctl3 = I915_READ(TV_H_CTL_3);
> > + vctl1 = I915_READ(TV_V_CTL_1);
> > + vctl2 = I915_READ(TV_V_CTL_2);
> > +
> > + tv_mode.htotal = (hctl1 & TV_HTOTAL_MASK) >> TV_HTOTAL_SHIFT;
> > + tv_mode.hsync_end = (hctl1 & TV_HSYNC_END_MASK) >> TV_HSYNC_END_SHIFT;
> > +
> > + tv_mode.hblank_start = (hctl3 & TV_HBLANK_START_MASK) >>
> > TV_HBLANK_START_SHIFT;
> > + tv_mode.hblank_end = (hctl3 & TV_HSYNC_END_MASK) >> TV_HBLANK_END_SHIFT;
> > +
> > + tv_mode.nbr_end = (vctl1 & TV_NBR_END_MASK) >> TV_NBR_END_SHIFT;
> > + tv_mode.vi_end_f1 = (vctl1 & TV_VI_END_F1_MASK) >> TV_VI_END_F1_SHIFT;
> > + tv_mode.vi_end_f2 = (vctl1 & TV_VI_END_F2_MASK) >> TV_VI_END_F2_SHIFT;
> > +
> > + tv_mode.vsync_len = (vctl2 & TV_VSYNC_LEN_MASK) >> TV_VSYNC_LEN_SHIFT;
> > + tv_mode.vsync_start_f1 = (vctl2 & TV_VSYNC_START_F1_MASK) >>
> > TV_VSYNC_START_F1_SHIFT;
> > + tv_mode.vsync_start_f2 = (vctl2 & TV_VSYNC_START_F2_MASK) >>
> > TV_VSYNC_START_F2_SHIFT;
> > +
> > + tv_mode.clock = pipe_config->port_clock;
> > +
> > + tv_mode.progressive = tv_ctl & TV_PROGRESSIVE;
> > +
> > + switch (tv_ctl & TV_OVERSAMPLE_MASK) {
> > + case TV_OVERSAMPLE_8X:
> > + tv_mode.oversample = 8;
> > + break;
> > + case TV_OVERSAMPLE_4X:
> > + tv_mode.oversample = 4;
> > + break;
> > + case TV_OVERSAMPLE_2X:
> > + tv_mode.oversample = 2;
> > + break;
> > + default:
> > + tv_mode.oversample = 1;
> > + break;
> > + }
> > +
> > + tmp = I915_READ(TV_WIN_POS);
> > + xpos = tmp >> 16;
> > + ypos = tmp & 0xffff;
> > +
> > + tmp = I915_READ(TV_WIN_SIZE);
> > + xsize = tmp >> 16;
> > + ysize = tmp & 0xffff;
> > +
> > + intel_tv_mode_to_mode(&mode, &tv_mode);
> > +
> > + DRM_DEBUG_KMS("TV mode:\n");
> > + drm_mode_debug_printmodeline(&mode);
> > +
> > + intel_tv_scale_mode_horiz(&mode, hdisplay,
> > + xpos, mode.hdisplay - xsize - xpos);
> > + intel_tv_scale_mode_vert(&mode, vdisplay,
> > + ypos, mode.vdisplay - ysize - ypos);
> > +
> > + adjusted_mode->crtc_clock = mode.clock;
> > }
> >
> > static bool
> > @@ -964,6 +1132,8 @@ intel_tv_compute_config(struct intel_encoder *encoder,
> > const struct tv_mode *tv_mode = intel_tv_mode_find(conn_state);
> > struct drm_display_mode *adjusted_mode =
> > &pipe_config->base.adjusted_mode;
> > + int hdisplay = adjusted_mode->crtc_hdisplay;
> > + int vdisplay = adjusted_mode->crtc_vdisplay;
> >
> > if (!tv_mode)
> > return false;
> > @@ -972,17 +1142,90 @@ intel_tv_compute_config(struct intel_encoder
> > *encoder,
> > return false;
> >
> > pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> > - adjusted_mode->crtc_clock = tv_mode->clock;
> > +
> > DRM_DEBUG_KMS("forcing bpc to 8 for TV\n");
> > pipe_config->pipe_bpp = 8*3;
> >
> > - /* TV has it's own notion of sync and other mode flags, so clear them.
> > */
> > - adjusted_mode->flags = 0;
> > + pipe_config->port_clock = tv_mode->clock;
> > +
> > + intel_tv_mode_to_mode(adjusted_mode, tv_mode);
> > +
> > + DRM_DEBUG_KMS("TV mode:\n");
> > + drm_mode_debug_printmodeline(adjusted_mode);
> >
> > /*
> > - * FIXME: We don't check whether the input mode is actually what we want
> > - * or whether userspace is doing something stupid.
> > + * The pipe scanline counter behaviour looks as follows when
> > + * using the TV encoder:
> > + *
> > + * time ->
> > + *
> > + * dsl=vtotal-1 | |
> > + * || ||
> > + * ___| | ___| |
> > + * / | / |
> > + * / | / |
> > + * dsl=0 ___/ |_____/ |
> > + * | | | | | |
> > + * ^ ^ ^ ^ ^
> > + * | | | | pipe vblank/first part of tv vblank
> > + * | | | bottom margin
> > + * | | active
> > + * | top margin
> > + * remainder of tv vblank
> > + *
> > + * When the TV encoder is used the pipe wants to run faster
> > + * than expected rate. During the active portion the TV
> > + * encoder stalls the pipe every few lines to keep it in
> > + * check. When the TV encoder reaches the bottom margin the
> > + * pipe simply stops. Once we reach the TV vblank the pipe is
> > + * no longer stalled and it runs at the max rate (apparently
> > + * oversample clock on gen3, cdclk on gen4). Once the pipe
> > + * reaches the pipe vtotal the pipe stops for the remainder
> > + * of the TV vblank/top margin. The pipe starts up again when
> > + * the TV encoder exits the top margin.
> > + *
> > + * To avoid huge hassles for vblank timestamping we scale
> > + * the pipe timings as if the pipe always runs at the average
> > + * rate it maintains during the active period. This also
> > + * gives us a reasonable guesstimate as to the pixel rate.
> > + * Due to the variation in the actual pipe speed the scanline
> > + * counter will give us slightly erroneous results during the
> > + * TV vblank/margins. But since vtotal was selected such that
> > + * it matches the average rate of the pipe during the active
> > + * portion the error shouldn't cause any serious grief to
> > + * vblank timestamps.
>
> Nice rev. enging and description. Was thinking for a while what is the
> max error the isssue you found adds wrt. the actual vblank timestamp,
> after your change. AFAIU it's the duration of the flats in the curve,
> that is
> max_err=+(bottom margin+remainder of tv vblank+top margin).
>
> Reviewed-by: Imre Deak <imre.d...@intel.com>
>
> > + *
> > + * For posterity here is the empirically derived formula
> > + * that gives us the maximum length of the pipe vblank
> > + * we can use without causing display corruption. Following
> > + * this would allow us to have a ticking scanline counter
> > + * everywhere except during the bottom margin (there the
> > + * pipe always stops). Ie. this would eliminate the second
> > + * flat portion of the above graph. However this would also
> > + * complicate vblank timestamping as the pipe vtotal would
> > + * no longer match the average rate the pipe runs at during
> > + * the active portion. Hence following this formula seems
> > + * more trouble that it's worth.
> > + *
> > + * if (IS_GEN4(dev_priv)) {
> > + * num = cdclk * (tv_mode->oversample >> !tv_mode->progressive);
> > + * den = tv_mode->clock;
> > + * } else {
> > + * num = tv_mode->oversample >> !tv_mode->progressive;
> > + * den = 1;
> > + * }
> > + * max_pipe_vblank_len ~=
> > + * (num * tv_htotal * (tv_vblank_len + top_margin)) /
> > + * (den * pipe_htotal);
> > */
> > + intel_tv_scale_mode_horiz(adjusted_mode, hdisplay,
> > + conn_state->tv.margins.left,
> > + conn_state->tv.margins.right);
> > + intel_tv_scale_mode_vert(adjusted_mode, vdisplay,
> > + conn_state->tv.margins.top,
> > + conn_state->tv.margins.bottom);
> > + drm_mode_set_crtcinfo(adjusted_mode, 0);
> > + adjusted_mode->name[0] = '\0';
> >
> > return true;
> > }
> > @@ -1411,52 +1654,41 @@ intel_tv_set_mode_type(struct drm_display_mode
> > *mode,
> > static int
> > intel_tv_get_modes(struct drm_connector *connector)
> > {
> > - struct drm_display_mode *mode_ptr;
> > const struct tv_mode *tv_mode = intel_tv_mode_find(connector->state);
> > - int j, count = 0;
> > - u64 tmp;
> > + int i, count = 0;
> >
> > - for (j = 0; j < ARRAY_SIZE(input_res_table);
> > - j++) {
> > - const struct input_res *input = &input_res_table[j];
> > - unsigned int hactive_s = input->w;
> > - unsigned int vactive_s = input->h;
> > -
> > - if (tv_mode->max_srcw && input->w > tv_mode->max_srcw)
> > - continue;
> > + for (i = 0; i < ARRAY_SIZE(input_res_table); i++) {
> > + const struct input_res *input = &input_res_table[i];
> > + struct drm_display_mode *mode;
> >
> > - if (input->w > 1024 && (!tv_mode->progressive
> > - && !tv_mode->component_only))
> > + if (input->w > 1024 &&
> > + !tv_mode->progressive &&
> > + !tv_mode->component_only)
> > continue;
> >
> > - mode_ptr = drm_mode_create(connector->dev);
> > - if (!mode_ptr)
> > + mode = drm_mode_create(connector->dev);
> > + if (!mode)
> > continue;
> >
> > - mode_ptr->hdisplay = hactive_s;
> > - mode_ptr->hsync_start = hactive_s + 1;
> > - mode_ptr->hsync_end = hactive_s + 64;
> > - if (mode_ptr->hsync_end <= mode_ptr->hsync_start)
> > - mode_ptr->hsync_end = mode_ptr->hsync_start + 1;
> > - mode_ptr->htotal = hactive_s + 96;
> > -
> > - mode_ptr->vdisplay = vactive_s;
> > - mode_ptr->vsync_start = vactive_s + 1;
> > - mode_ptr->vsync_end = vactive_s + 32;
> > - if (mode_ptr->vsync_end <= mode_ptr->vsync_start)
> > - mode_ptr->vsync_end = mode_ptr->vsync_start + 1;
> > - mode_ptr->vtotal = vactive_s + 33;
> > -
> > - tmp = mul_u32_u32(tv_mode->refresh, mode_ptr->vtotal);
> > - tmp *= mode_ptr->htotal;
> > - tmp = div_u64(tmp, 1000000);
> > - mode_ptr->clock = (int) tmp;
> > -
> > - intel_tv_set_mode_type(mode_ptr, tv_mode);
> > + /*
> > + * We take the TV mode and scale it to look
> > + * like it had the expected h/vdisplay. This
> > + * provides the most information to userspace
> > + * about the actual timings of the mode. We
> > + * do ignore the margins though.
> > + */
> > + intel_tv_mode_to_mode(mode, tv_mode);
> > + if (count == 0) {
> > + DRM_DEBUG_KMS("TV mode:\n");
> > + drm_mode_debug_printmodeline(mode);
> > + }
> > + intel_tv_scale_mode_horiz(mode, input->w, 0, 0);
> > + intel_tv_scale_mode_vert(mode, input->h, 0, 0);
> > + intel_tv_set_mode_type(mode, tv_mode);
> >
> > - drm_mode_set_name(mode_ptr);
> > + drm_mode_set_name(mode);
> >
> > - drm_mode_probed_add(connector, mode_ptr);
> > + drm_mode_probed_add(connector, mode);
> > count++;
> > }
> >
> > --
> > 2.18.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel
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