[PATCH] drm/msm/dsi: Calculate link clock rates with updated dsi->lanes

[Archit Taneja]

After the commit mentioned below, we start computing the byte and pixel
clocks (dsi_calc_clk_rate) in the DSI bridge's mode_set() op. The
calculation involves the number of DSI lanes being used by the
downstream bridge/panel.

If the downstream bridge/panel tries to change the number of DSI lanes
(as done in the ADV7533 driver) in its mode_set() op, then our DSI
host driver will not have the correct number of lanes when computing
byte/pixel clocks.

Fix this by delaying the clock rate calculation in the DSI bridge
enable path. In particular, compute the clock rates in
msm_dsi_host_get_phy_clk_req().

This fixes the DSI host error interrupts seen when we try to switch
between modes that require different number of lanes (4 to 3 lanes, or
vice versa) on db410c. The error interrupts occur since the byte/pixel
clock rates aren't according to what the DSI video mode timing engine
expects.

Fixes: b62aa70a98c5 ("drm/msm/dsi: Move PHY operations out of host")
Signed-off-by: Archit Taneja <architt at codeaurora.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 9e9c5696bc03..c7b612c3d771 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -2137,6 +2137,13 @@ void msm_dsi_host_get_phy_clk_req(struct mipi_dsi_host *host,
 	struct msm_dsi_phy_clk_request *clk_req)
 {
 	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
+	int ret;
+
+	ret = dsi_calc_clk_rate(msm_host);
+	if (ret) {
+		pr_err("%s: unable to calc clk rate, %d\n", __func__, ret);
+		return;
+	}
 
 	clk_req->bitclk_rate = msm_host->byte_clk_rate * 8;
 	clk_req->escclk_rate = msm_host->esc_clk_rate;
@@ -2280,7 +2287,6 @@ int msm_dsi_host_set_display_mode(struct mipi_dsi_host *host,
 					struct drm_display_mode *mode)
 {
 	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
-	int ret;
 
 	if (msm_host->mode) {
 		drm_mode_destroy(msm_host->dev, msm_host->mode);
@@ -2293,12 +2299,6 @@ int msm_dsi_host_set_display_mode(struct mipi_dsi_host *host,
 		return -ENOMEM;
 	}
 
-	ret = dsi_calc_clk_rate(msm_host);
-	if (ret) {
-		pr_err("%s: unable to calc clk rate, %d\n", __func__, ret);
-		return ret;
-	}
-
 	return 0;
 }
 
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