Patch "clk: imx6: initialize GPU clocks" has been added to the 4.4-stable tree

Patch "clk: imx6: initialize GPU clocks" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    clk: imx6: initialize GPU clocks

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-imx6-initialize-gpu-clocks.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d8846023aed1293e54d33499558fc2aa2b2f393f Mon Sep 17 00:00:00 2001
From: Lucas Stach <l.stach@pengutronix.de>
Date: Fri, 16 Sep 2016 11:16:11 +0200
Subject: clk: imx6: initialize GPU clocks

From: Lucas Stach <l.stach@pengutronix.de>

commit d8846023aed1293e54d33499558fc2aa2b2f393f upstream.

Initialize the GPU clock muxes to sane inputs. Until now they have
not been changed from their default values, which means that both
GPU3D shader and GPU2D core were fed by clock inputs whose rates
exceed the maximium allowed frequency of the cores by as much as
200MHz.

This fixes a severe GPU stability issue on i.MX6DL.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/clk/imx/clk-imx6q.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- a/drivers/clk/imx/clk-imx6q.c
+++ b/drivers/clk/imx/clk-imx6q.c
@@ -550,6 +550,24 @@ static void __init imx6q_clocks_init(str
 	if (IS_ENABLED(CONFIG_PCI_IMX6))
 		clk_set_parent(clk[IMX6QDL_CLK_LVDS1_SEL], clk[IMX6QDL_CLK_SATA_REF_100M]);
 
+	/*
+	 * Initialize the GPU clock muxes, so that the maximum specified clock
+	 * rates for the respective SoC are not exceeded.
+	 */
+	if (clk_on_imx6dl()) {
+		clk_set_parent(clk[IMX6QDL_CLK_GPU3D_CORE_SEL],
+			       clk[IMX6QDL_CLK_PLL2_PFD1_594M]);
+		clk_set_parent(clk[IMX6QDL_CLK_GPU2D_CORE_SEL],
+			       clk[IMX6QDL_CLK_PLL2_PFD1_594M]);
+	} else if (clk_on_imx6q()) {
+		clk_set_parent(clk[IMX6QDL_CLK_GPU3D_CORE_SEL],
+			       clk[IMX6QDL_CLK_MMDC_CH0_AXI]);
+		clk_set_parent(clk[IMX6QDL_CLK_GPU3D_SHADER_SEL],
+			       clk[IMX6QDL_CLK_PLL2_PFD1_594M]);
+		clk_set_parent(clk[IMX6QDL_CLK_GPU2D_CORE_SEL],
+			       clk[IMX6QDL_CLK_PLL3_USB_OTG]);
+	}
+
 	imx_register_uart_clocks(uart_clks);
 }
 CLK_OF_DECLARE(imx6q, "fsl,imx6q-ccm", imx6q_clocks_init);


Patches currently in stable-queue which might be from l.stach@pengutronix.de are

queue-4.4/clk-imx6-initialize-gpu-clocks.patch