| Message ID | 1507817775-31550-1-git-send-email-jsarha@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@windriver.com> > Fixes: 11abbc9f39e0 ("drm/tilcdc: Set framebuffer DMA address to HW only if CRTC is enabled") > Cc: <stable@vger.kernel.org> # v4.11+ > Signed-off-by: Jyri Sarha <jsarha@ti.com> > --- > 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
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; + + if (totalframes < U32_MAX / 1000u) + return (1000u * totalframes) / mode->clock; + else + return 10u * ((100u * totalframes) / mode->clock); +} + static void tilcdc_crtc_set_mode(struct drm_crtc *crtc) { struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc); @@ -459,6 +470,9 @@ static void tilcdc_crtc_set_mode(struct drm_crtc *crtc) drm_framebuffer_get(fb); crtc->hwmode = crtc->state->adjusted_mode; + + tilcdc_crtc->frametime_us = + tilcdc_mode_frametime(&crtc->hwmode); } static void tilcdc_crtc_enable(struct drm_crtc *crtc) @@ -642,7 +656,7 @@ int tilcdc_crtc_update_fb(struct drm_crtc *crtc, spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags); next_vblank = ktime_add_us(tilcdc_crtc->last_vblank, - 1000000 / crtc->hwmode.vrefresh); + tilcdc_crtc->frametime_us); tdiff = ktime_to_us(ktime_sub(next_vblank, ktime_get())); if (tdiff < TILCDC_VBLANK_SAFETY_THRESHOLD_US)
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@windriver.com> Fixes: 11abbc9f39e0 ("drm/tilcdc: Set framebuffer DMA address to HW only if CRTC is enabled") Cc: <stable@vger.kernel.org> # v4.11+ Signed-off-by: Jyri Sarha <jsarha@ti.com> --- 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(-)