video: tegra: dc: maintain custom CMU settings across suspend cycles

The DC driver currently clears its CMU cache on suspend, and writes
pdata CMU settings on resume. In some situations we may choose to change
CMU data during runtime; the current behavior will reset that data on
suspend/resume cycles.

This change removes cache clearing on suspend, and on resume the driver
uses its cache instead of pdata to populate CMU.

Note 1: The original purpose of clearing the cache on suspend was to
satisfy a memcmp() and force a CMU update. Since then, memcmp was
replaced by an address comparison, so that's no longer a concern.

Note 2: This change affects dc_init(), which is called on resume and
during DC probe. During resume, CMU cache is already populated. During
probe, CMU cache is populated by set_out(), called before dc_init().

Bug 1535044

Change-Id: I26b05bbede11d9a11a0ac307e8e8da97aefa2420
Signed-off-by: Daniel Solomon <daniels@nvidia.com>
Reviewed-on: http://git-master/r/658190
(cherry picked from commit 2f46feb9c25a276e63ded41ddec20b61e456e4d5)
Reviewed-on: http://git-master/r/664722
(cherry picked from commit 2d6296391e837ed47b523795fd425c873962a634)
Reviewed-on: http://git-master/r/677139
Reviewed-by: Mitch Luban <mluban@nvidia.com>
Tested-by: Mitch Luban <mluban@nvidia.com>

diff --git a/drivers/video/tegra/dc/dc.c b/drivers/video/tegra/dc/dc.c
index 5dd219ed530c97eea8af9ed1733b3edd3dc52432..284c287e6ba4821865bdbabb6937eeddebefdb20 100644 (file)
--- a/drivers/video/tegra/dc/dc.c
+++ b/drivers/video/tegra/dc/dc.c
@@ -2084,16 +2084,6 @@ static int tegra_dc_set_out(struct tegra_dc *dc, struct tegra_dc_out *out)
                                dc->out->h_size, dc->out->v_size,
                                dc->mode.pclk);
                dc->initialized = true;
-
-#ifdef CONFIG_TEGRA_DC_CMU
-               /*
-                * If the bootloader already set the mode, assume the CMU
-                * parameters are also correctly set. It would be better to
-                * read them, but unfortunately there is no reliable and
-                * flicker-free way to do this!
-                */
-               tegra_dc_cache_cmu(dc, tegra_dc_get_cmu(dc));
-#endif
        } else if (out->n_modes > 0)
                tegra_dc_set_mode(dc, &dc->out->modes[0]);
 
@@ -2160,6 +2150,11 @@ static int tegra_dc_set_out(struct tegra_dc *dc, struct tegra_dc_out *out)
                dc->out_ops = NULL;
                break;
        }
+
+#ifdef CONFIG_TEGRA_DC_CMU
+       tegra_dc_cache_cmu(dc, tegra_dc_get_cmu(dc));
+#endif
+
        if (dc->out_ops && dc->out_ops->init) {
                err = dc->out_ops->init(dc);
                if (err < 0) {
@@ -3096,7 +3091,7 @@ static int tegra_dc_init(struct tegra_dc *dc)
 #endif
 
 #ifdef CONFIG_TEGRA_DC_CMU
-       _tegra_dc_update_cmu_aligned(dc, tegra_dc_get_cmu(dc), true);
+       _tegra_dc_update_cmu_aligned(dc, &dc->cmu, true);
 #endif
        tegra_dc_set_color_control(dc);
        for_each_set_bit(i, &dc->valid_windows, DC_N_WINDOWS) {