Bootloader enabled display, when the driver is built-in (rather than a
module loaded after CCF/genpd disable "unused" clocks/powerdomains)
causes problems since the driver thinks the clocks are off, but in fact
they are on. This causes (for example) clk_set_rate() to fail.
A better solution would be to support display handover from bootloader,
but that will require some CCF+genpd changes before that is possible.
So until then, we need this workaround.
Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 0f7324a686ca..589818d027e4 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -418,6 +418,40 @@ static int dsi_clk_init(struct msm_dsi_host *msm_host)
__func__, ret);
}
}
+
+ /*
+ * If the bootloader enables the display, and the driver is
+ * built-in (as opposed to module, loaded after clk/genpd
+ * framework disables "unused" clocks and power domains, we
+ * would already have clocks enabled. But kms thinks that
+ * everything is disabled. This causes problems, for ex,
+ * when trying to clk_set_rate() on bootloader enabled
+ * clocks.
+ *
+ * Work around this for now, until we have a better solution
+ * in place, by doing an extra enable/disable. This forces
+ * things to a disabled state.
+ */
+ if (cfg_hnd->major == MSM_DSI_VER_MAJOR_6G) {
+ clk_prepare_enable(msm_host->byte_clk);
+ clk_prepare_enable(msm_host->pixel_clk);
+ clk_prepare_enable(msm_host->esc_clk);
+
+ clk_disable_unprepare(msm_host->esc_clk);
+ clk_disable_unprepare(msm_host->pixel_clk);
+ clk_disable_unprepare(msm_host->byte_clk);
+ } else {
+ clk_prepare_enable(msm_host->byte_clk);
+ clk_prepare_enable(msm_host->esc_clk);
+ clk_prepare_enable(msm_host->src_clk);
+ clk_prepare_enable(msm_host->pixel_clk);
+
+ clk_disable_unprepare(msm_host->pixel_clk);
+ clk_disable_unprepare(msm_host->src_clk);
+ clk_disable_unprepare(msm_host->esc_clk);
+ clk_disable_unprepare(msm_host->byte_clk);
+ }
+
exit:
return ret;
}
--
2.13.6
--
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