On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
> In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
> and timing related limitations leading to SYNCLOST errors. Whenever the image
> window is moved towards the right of the screen SYNCLOST errors become
> frequent. Checks have been implemented to see that DISPC driver rejects
> configuration exceeding above limitations.
>
> This code was successfully tested on OMAP3. This code is written based on code
> written by Ville Syrjälä <ville.syrjala@xxxxxxxxx> in Linux OMAP kernel. Ville
> Syrjälä <ville.syrjala@xxxxxxxxx> had added checks for video overlay horizontal
> timing and DISPC horizontal blanking length limitations.
>
> Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@xxxxxx>
> ---
> drivers/video/omap2/dss/dispc.c | 97 +++++++++++++++++++++++++++++----------
> 1 files changed, 72 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
> index 5a1963e..d8a1672 100644
> --- a/drivers/video/omap2/dss/dispc.c
> +++ b/drivers/video/omap2/dss/dispc.c
> @@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
> }
> }
>
> +static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
> + u16 width, u16 height, u16 out_width, u16 out_height)
I think the function could be named check_horiz_timing_omap3 or
something. It's kinda hard to realize that this is an omap3 work-around.
Perhaps a short comment above the function would be in order.
> +{
> + int DS = DIV_ROUND_UP(height, out_height);
> + struct omap_dss_device *dssdev = dispc_mgr_get_device(channel);
> + struct omap_video_timings t = dssdev->panel.timings;
> + unsigned long nonactive, lclk, pclk;
> + static const u8 limits[3] = { 8, 10, 20 };
> + u64 val, blank;
> + int i;
> +
> + nonactive = t.x_res + t.hfp + t.hsw + t.hbp - out_width;
> + pclk = dispc_mgr_pclk_rate(channel);
> + lclk = dispc_mgr_lclk_rate(channel);
> +
> + i = 0;
> + if (out_height < height)
> + i++;
> + if (out_width < width)
> + i++;
> + blank = div_u64((u64)(t.hbp + t.hsw + t.hfp) * lclk, pclk);
> + DSSDBG("blanking period + ppl = %llu (limit = %u)\n", blank, limits[i]);
> + if (blank <= limits[i])
> + return -EINVAL;
> +
> + /*
> + * Pixel data should be prepared before visible display point starts.
> + * So, atleast DS-2 lines must have already been fetched by DISPC
> + * during nonactive - pos_x period.
> + */
> + val = div_u64((u64)(nonactive - pos_x) * lclk, pclk);
> + DSSDBG("(nonactive - pos_x) * pcd = %llu,"
> + " max(0, DS - 2) * width = %d\n",
> + val, max(0, DS - 2) * width);
> + if (val < max(0, DS - 2) * width)
> + return -EINVAL;
> +
> + /*
> + * All lines need to be refilled during the nonactive period of which
> + * only one line can be loaded during the active period. So, atleast
> + * DS - 1 lines should be loaded during nonactive period.
> + */
> + val = div_u64((u64)nonactive * lclk, pclk);
> + DSSDBG("nonactive * pcd = %llu, max(0, DS - 1) * width = %d\n",
> + val, max(0, DS - 1) * width);
> + if (val < max(0, DS - 1) * width)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> static unsigned long calc_fclk_five_taps(enum omap_channel channel, u16 width,
> u16 height, u16 out_width, u16 out_height,
> enum omap_color_mode color_mode)
> @@ -1702,7 +1753,7 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
> enum omap_channel channel, u16 width, u16 height,
> u16 out_width, u16 out_height,
> enum omap_color_mode color_mode, bool *five_taps,
> - int *x_predecim, int *y_predecim)
> + int *x_predecim, int *y_predecim, u16 pos_x)
> {
> struct omap_overlay *ovl = omap_dss_get_overlay(plane);
> const int maxdownscale = dss_feat_get_param_max(FEAT_PARAM_DOWNSCALE);
> @@ -1778,6 +1829,9 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
> fclk = calc_fclk_five_taps(channel, in_width, in_height,
> out_width, out_height, color_mode);
>
> + error = check_horiz_timing(channel, pos_x, in_width,
> + in_height, out_width, out_height);
> +
> if (in_width > maxsinglelinewidth)
> if (in_height > out_height &&
> in_height < out_height * 2)
> @@ -1785,7 +1839,7 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
> if (!*five_taps)
> fclk = calc_fclk(channel, in_width, in_height,
> out_width, out_height);
> - error = (in_width > maxsinglelinewidth * 2 ||
> + error = (error || in_width > maxsinglelinewidth * 2 ||
> (in_width > maxsinglelinewidth && *five_taps) ||
> !fclk || fclk > dispc_fclk_rate());
> if (error) {
> @@ -1801,6 +1855,12 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
> } while (decim_x <= *x_predecim && decim_y <= *y_predecim
> && error);
>
> + if (check_horiz_timing(channel, pos_x, width, height,
> + out_width, out_height)){
> + DSSERR("horizontal timing too tight\n");
> + return -EINVAL;
> + }
> +
> if (in_width > (maxsinglelinewidth * 2)) {
> DSSERR("Cannot setup scaling");
> DSSERR("width exceeds maximum width possible");
> @@ -1901,7 +1961,7 @@ int dispc_ovl_setup(enum omap_plane plane, struct omap_overlay_info *oi,
>
> r = dispc_ovl_calc_scaling(plane, channel, in_width, in_height,
> out_width, out_height, oi->color_mode, &five_taps,
> - &x_predecim, &y_predecim);
> + &x_predecim, &y_predecim, oi->pos_x);
> if (r)
> return r;
>
> @@ -2472,32 +2532,19 @@ unsigned long dispc_fclk_rate(void)
>
> unsigned long dispc_mgr_lclk_rate(enum omap_channel channel)
> {
> - struct platform_device *dsidev;
> - int lcd;
> - unsigned long r;
> - u32 l;
> + unsigned long r = dispc_fclk_rate();
>
> - l = dispc_read_reg(DISPC_DIVISORo(channel));
> + if (dispc_mgr_is_lcd(channel)) {
> + u32 l;
> + int lcd;
>
> - lcd = FLD_GET(l, 23, 16);
> + l = dispc_read_reg(DISPC_DIVISORo(channel));
> + lcd = FLD_GET(l, 23, 16);
>
> - switch (dss_get_lcd_clk_source(channel)) {
> - case OMAP_DSS_CLK_SRC_FCK:
> - r = clk_get_rate(dispc.dss_clk);
> - break;
> - case OMAP_DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC:
> - dsidev = dsi_get_dsidev_from_id(0);
> - r = dsi_get_pll_hsdiv_dispc_rate(dsidev);
> - break;
> - case OMAP_DSS_CLK_SRC_DSI2_PLL_HSDIV_DISPC:
> - dsidev = dsi_get_dsidev_from_id(1);
> - r = dsi_get_pll_hsdiv_dispc_rate(dsidev);
> - break;
> - default:
> - BUG();
> + return r / lcd;
> + } else {
> + return r;
> }
> -
> - return r / lcd;
> }
I don't the change to dispc_mgr_lclk_rate has anything to do with this
patch (fixing omap3 sync lost error). Shouldn't it be a separate fix?
Tomi
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