Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
On 12/10/17 17:16, Jyri Sarha wrote:
> We need the frame refresh time to check if we are too close to
> vertical sync when updating the two framebuffer DMA registers and risk
> a collision. This new method is more accurate that the previous that
> based on mode's vrefresh value, which itself may also be inaccurate
> or not even initialized.
>
> Reported-by: Kevin Hao <kexin.hao@xxxxxxxxxxxxx>
> Fixes: 11abbc9f39e0 ("drm/tilcdc: Set framebuffer DMA address to HW only if CRTC is enabled")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.11+
> Signed-off-by: Jyri Sarha <jsarha@xxxxxx>
> ---
> This patch is inteded to replace this:
> https://lists.freedesktop.org/archives/dri-devel/2017-October/154556.html
>
> drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> index 704db24..b2f2170 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> @@ -48,6 +48,7 @@ struct tilcdc_crtc {
> unsigned int lcd_fck_rate;
>
> ktime_t last_vblank;
> + unsigned int frametime_us;
>
> struct drm_framebuffer *curr_fb;
> struct drm_framebuffer *next_fb;
> @@ -292,6 +293,16 @@ static void tilcdc_crtc_set_clk(struct drm_crtc *crtc)
> LCDC_V2_CORE_CLK_EN);
> }
>
> +u32 tilcdc_mode_frametime(const struct drm_display_mode *mode)
> +{
> + u32 totalframes = mode->htotal * mode->vtotal;
"totalframes"? Shouldn't it be total pixels (including blanking pixels)?
Or maybe "hvtotal", mimicking the htotal and vtotal.
> +
> + if (totalframes < U32_MAX / 1000u)
> + return (1000u * totalframes) / mode->clock;
> + else
> + return 10u * ((100u * totalframes) / mode->clock);
Just pick one, I don't think there's benefit in the above if. Perhaps go
via u64 div.
Tomi