2015-05-18 Daniel Stone <daniel@xxxxxxxxxxxxx>:
> Hi,
>
> On Monday, May 18, 2015, Gustavo Padovan <gustavo@xxxxxxxxxxx> wrote:
>
> > Hi Tobias,
> >
> > 2015-05-15 Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx <javascript:;>>:
> > > I did another run with drm.debug=0xff and also tried to figure out where
> > the
> > > div-by-zero comes from.
> > >
> > > The only division I see is in fimd_calc_clkdiv() (which is called by
> > > fimd_commit()). So it looks like 'ideal_clk' is zero when calling
> > > DIV_ROUND_UP().
> > >
> > > 'htotal' and 'vtotal' can't be zero, since this is checked early in
> > > fimd_commit(). So 'vrefresh' has to be zero. Maybe this helps?
> >
> > What is is the output when you run with this patch:
> >
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > index 12ab80c..f5d215d 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > @@ -310,6 +310,8 @@ static u32 fimd_calc_clkdiv(struct fimd_context *ctx,
> > unsigned long ideal_clk = mode->htotal * mode->vtotal *
> > mode->vrefresh;
> > u32 clkdiv;
> >
> > + DRM_DEBUG_KMS("vrefresh %d\n", mode->vrefresh);
> > +
> > if (ctx->i80_if) {
> > /*
> > * The frame done interrupt should be occurred prior to the
> > @@ -328,6 +330,7 @@ static bool fimd_mode_fixup(struct exynos_drm_crtc
> > *crtc,
> > const struct drm_display_mode *mode,
> > struct drm_display_mode *adjusted_mode)
> > {
> > + DRM_DEBUG_KMS("vrefresh %d\n", adjusted_mode->vrefresh);
> > if (adjusted_mode->vrefresh == 0)
> > adjusted_mode->vrefresh = FIMD_DEFAULT_FRAMERATE;
> >
>
> vrefresh can legitimately be zero, which makes this FIMD_DEFAULT_FRAMERATE
> assignment problematic rather than harmless.
>
> If it's zero, you can find a vrefresh value with drm_mode_vrefresh, which
> will calculate it for you.
So better try this. Ideally fimd_mode_fixup should go away too, I'll do a proper
patch once we know this works.
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 12ab80c..363353b 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -307,9 +307,17 @@ static void fimd_iommu_detach_devices(struct fimd_context *ctx)
static u32 fimd_calc_clkdiv(struct fimd_context *ctx,
const struct drm_display_mode *mode)
{
- unsigned long ideal_clk = mode->htotal * mode->vtotal * mode->vrefresh;
+ unsigned long ideal_clk;
+ int vrefresh;
u32 clkdiv;
+ if (mode->vrefresh == 0)
+ vrefresh = drm_mode_vrefresh(mode);
+ else
+ vrefresh = mode->vrefresh;
+
+ ideal_clk = mode->htotal * mode->vtotal * vrefresh;
+
if (ctx->i80_if) {
/*
* The frame done interrupt should be occurred prior to the
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