Re: [PATCH] clk: qcom: clk-rcg2: fix gfx3d frequency calculation

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Tue 19 Apr 18:54 CDT 2022, Dmitry Baryshkov wrote:

> Since the commit 948fb0969eae ("clk: Always clamp the rounded rate"),
> the clk_core_determine_round_nolock() would clamp the requested rate
> between min and max rates from the rate request. Normally these fields
> would be filled by clk_core_get_boundaries() called from
> clk_round_rate().
> 
> However clk_gfx3d_determine_rate() uses a manually crafted rate request,
> which did not have these fields filled. Thus the requested frequency
> would be clamped to 0, resulting in weird frequencies being requested
> from the hardware.
> 
> Fix this by filling min_rate and max_rate to the values valid for the
> respective PLLs (0 and ULONG_MAX).
> 
> Fixes: 948fb0969eae ("clk: Always clamp the rounded rate")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Stephen, please pick this for -fixes.

Thanks,
Bjorn

> ---
>  drivers/clk/qcom/clk-rcg2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
> index f675fd969c4d..e9c357309fd9 100644
> --- a/drivers/clk/qcom/clk-rcg2.c
> +++ b/drivers/clk/qcom/clk-rcg2.c
> @@ -818,7 +818,7 @@ EXPORT_SYMBOL_GPL(clk_pixel_ops);
>  static int clk_gfx3d_determine_rate(struct clk_hw *hw,
>  				    struct clk_rate_request *req)
>  {
> -	struct clk_rate_request parent_req = { };
> +	struct clk_rate_request parent_req = { .min_rate = 0, .max_rate = ULONG_MAX };
>  	struct clk_rcg2_gfx3d *cgfx = to_clk_rcg2_gfx3d(hw);
>  	struct clk_hw *xo, *p0, *p1, *p2;
>  	unsigned long p0_rate;
> -- 
> 2.35.1
>