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FAILED: patch "[PATCH] drm/msm/dsi: dsi_phy_14nm: Take ready-bit into account in" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Oct 18, 2021

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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90b7c1c66132c20e8a550006011a3cbfb73dbfc1 Mon Sep 17 00:00:00 2001
From: Marijn Suijten <[email protected]>
Date: Mon, 6 Sep 2021 22:25:51 +0200
Subject: [PATCH] drm/msm/dsi: dsi_phy_14nm: Take ready-bit into account in
poll_for_ready

The downstream driver models this PLL lock check as an if-elseif-else. The only way to reach the else case where pll_locked=true [1] is by succeeding both readl_poll_timeout_atomic calls (which return zero on success) in the if _and_ elseif condition. Hence both the "lock" and "ready" bit need to be tested in the SM_READY_STATUS register before considering the PLL locked and ready to go.

Tested on the Sony Xperia XA2 Ultra (nile-discovery, sdm630).

[1]: https://source.codeaurora.org/quic/la/kernel/msm-4.19/tree/drivers/clk/qcom/mdss/mdss-dsi-pll-14nm-util.c?h=LA.UM.9.2.1.r1-08000-sdm660.0#n302

Fixes f079f6d999cb ("drm/msm/dsi: Add PHY/PLL for 8x96")
Signed-off-by Marijn Suijten <[email protected]>
Reviewed-by Dmitry Baryshkov <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Dmitry Baryshkov <[email protected]>
Signed-off-by Rob Clark <[email protected]>
drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c +15 -15
index d13552b2213b..5b4e991f220d 100644
@@ -110,14 +110,13 @@ static struct dsi_pll_14nm *pll_14nm_list[DSI_MAX];
 static bool pll_14nm_poll_for_ready(struct dsi_pll_14nm *pll_14nm,
 				    u32 nb_tries, u32 timeout_us)
 {
-	bool pll_locked = false;
+	bool pll_locked = false, pll_ready = false;
 	void __iomem *base = pll_14nm->phy->pll_base;
 	u32 tries, val;
 
 	tries = nb_tries;
 	while (tries--) {
-		val = dsi_phy_read(base +
-			       REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS);
+		val = dsi_phy_read(base + REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS);
 		pll_locked = !!(val & BIT(5));
 
 		if (pll_locked)

@@ -126,23 +125,24 @@ static bool pll_14nm_poll_for_ready(struct dsi_pll_14nm *pll_14nm,
 		udelay(timeout_us);
 	}
 
-	if (!pll_locked) {
-		tries = nb_tries;
-		while (tries--) {
-			val = dsi_phy_read(base +
-				REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS);
-			pll_locked = !!(val & BIT(0));
+	if (!pll_locked)
+		goto out;
 
-			if (pll_locked)
-				break;
+	tries = nb_tries;
+	while (tries--) {
+		val = dsi_phy_read(base + REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS);
+		pll_ready = !!(val & BIT(0));
 
-			udelay(timeout_us);
-		}
+		if (pll_ready)
+			break;
+
+		udelay(timeout_us);
 	}
 
-	DBG("DSI PLL is %slocked", pll_locked ? "" : "*not* ");
+out:
+	DBG("DSI PLL is %slocked, %sready", pll_locked ? "" : "*not* ", pll_ready ? "" : "*not* ");
 
-	return pll_locked;
+	return pll_locked && pll_ready;
 }
 
 static void dsi_pll_14nm_config_init(struct dsi_pll_config *pconf)