On Fri, 2017-02-24 at 12:54 +1030, Joel Stanley wrote:
> On Fri, Feb 24, 2017 at 9:23 AM, Benjamin Herrenschmidt
> <benh@xxxxxxxxxxxxxxxxxxx> wrote:
> > Some braces were missing causing an incorrect calculation.
> >
> > Y.C. Chen from Aspeed provided me with the right formula
> > which I tested on AST2400 and 2500.
>
> Y. C. Chen, can you point out this calculation in the programming
> guide?
>
> All of the PLL calculations I can find in the ast2400 documentation
> are different to this one.
Different PLL register, see my other email. I've checked the result
of the calculation on our AST2500 and AST2400 machines.
Cheers,
Ben.
> Cheers,
>
> Joel
>
> >
> > The MCLK isn't currently used by the driver (it will eventually
> > to filter modes) so the issue isn't catastrophic.
> >
> > Also make the printed value a bit more meaningful
> >
> > Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/ast/ast_main.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/ast/ast_main.c
> > b/drivers/gpu/drm/ast/ast_main.c
> > index 718c15b..d194af3 100644
> > --- a/drivers/gpu/drm/ast/ast_main.c
> > +++ b/drivers/gpu/drm/ast/ast_main.c
> > @@ -352,7 +352,7 @@ static int ast_get_dram_info(struct drm_device
> > *dev)
> > div = 0x1;
> > break;
> > }
> > - ast->mclk = ref_pll * (num + 2) / (denum + 2) * (div *
> > 1000);
> > + ast->mclk = ref_pll * (num + 2) / ((denum + 2) * (div *
> > 1000));
> > return 0;
> > }
> >
> > @@ -496,7 +496,9 @@ int ast_driver_load(struct drm_device *dev,
> > unsigned long flags)
> > if (ret)
> > goto out_free;
> > ast->vram_size = ast_get_vram_info(dev);
> > - DRM_INFO("dram %d %d %d %08x\n", ast->mclk, ast-
> > >dram_type, ast->dram_bus_width, ast->vram_size);
> > + DRM_INFO("dram MCLK=%u Mhz type=%d bus_width=%d
> > size=%08x\n",
> > + ast->mclk, ast->dram_type,
> > + ast->dram_bus_width, ast->vram_size);
> > }
> >
> > if (need_post)
> > --
> > 2.9.3
> >
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