Re: [PATCH] imx-drm: imx-hdmi: fix hdmi hotplug detection initial state

[Fabio Estevam <festevam@gmail.com>]

On Mon, Jun 9, 2014 at 3:38 PM, Fabio Estevam <festevam@gmail.com> wrote:
> On Mon, Jun 9, 2014 at 3:15 PM, Fabio Estevam <festevam@gmail.com> wrote:
>>> I wonder if the problem is that HDMI and LVDS are interfering with each
>>> other wrt the required pixel clock, and LVDS is winning.  If we have
>>> HDMI enabled, many HDMI sinks will only work if we set one of their
>>> supported modes (with the dot clock within 1% - though some sinks are
>>> more lenient).
>>
>> Yes, it seems this is the case.
>
> I tested not using pll5 as the parent of LVDS:
>
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -439,12 +439,6 @@ static void __init imx6q_clocks_init(struct device_node *cc
>         clk_register_clkdev(clk[gpt_ipg_per], "per", "imx-gpt.0");
>         clk_register_clkdev(clk[enet_ref], "enet_ref", NULL);
>
> -       if ((imx_get_soc_revision() != IMX_CHIP_REVISION_1_0) ||
> -           cpu_is_imx6dl()) {
> -               clk_set_parent(clk[ldb_di0_sel], clk[pll5_video_div]);
> -               clk_set_parent(clk[ldb_di1_sel], clk[pll5_video_div]);
> -       }
> -
>         clk_set_parent(clk[ipu1_di0_pre_sel], clk[pll5_video_div]);
>         clk_set_parent(clk[ipu1_di1_pre_sel], clk[pll5_video_div]);
>         clk_set_parent(clk[ipu2_di0_pre_sel], clk[pll5_video_div]);
>
>
> Then the HDMI detection works fine and I get images on both HDMI and LVDS.
>
> I understand that many LVDS panels need a frequency range that can
> only be obtained via PLL5 though.

Also tested keeping LVDS parent as PLL5 and reverted this commit:

commit 17b9b3b9e88ac6564689283a08034faf2c048fdb
Author: Sascha Hauer <s.hauer@pengutronix.de>
Date:   Mon Apr 14 16:20:39 2014 +0200

    ARM: imx6q: clk: Parent DI clocks to video PLL via di_pre_sel

    Route the video PLL to the display interface clocks via the di_pre_sel
    and di_sel muxes by default.

    Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
    Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
    Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
    Signed-off-by: Shawn Guo <shawn.guo@freescale.com>


,then HDMI and LVDS work at the same time.