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SubjectRe: [PATCH v2 05/11] clk: qcom: gcc-msm8998: Mark gpu_cfg_ahb_clk as critical
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Quoting AngeloGioacchino Del Regno (2021-01-14 14:10:53)
> The GPU IOMMU depends on this clock and the hypervisor will crash
> the SoC if this clock gets disabled because the secure contexts
> that have been set on this IOMMU by the bootloader will become
> unaccessible (or they get reset).
> Mark this clock as critical to avoid this issue when the Adreno
> GPU is enabled.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
> ---
> drivers/clk/qcom/gcc-msm8998.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/clk/qcom/gcc-msm8998.c b/drivers/clk/qcom/gcc-msm8998.c
> index c8d4c0348952..afea60a3ef43 100644
> --- a/drivers/clk/qcom/gcc-msm8998.c
> +++ b/drivers/clk/qcom/gcc-msm8998.c
> @@ -2081,6 +2081,12 @@ static struct clk_branch gcc_gpu_cfg_ahb_clk = {
> .hw.init = &(struct clk_init_data){
> .name = "gcc_gpu_cfg_ahb_clk",
> .ops = &clk_branch2_ops,
> + /*
> + * The GPU IOMMU depends on this clock and hypervisor
> + * will crash the SoC if this clock goes down, due to
> + * secure contexts protection.
> + */
> + .flags = CLK_IS_CRITICAL,
> },
> },

Please send a followup patch that hits the branch on at probe time and
removes this clk from the kernel. That will save some memory and
overhead of worrying about this clk.

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