4.14-stable review patch. If anyone has any objections, please let me know.
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From: Jyri Sarha jsarha@ti.com
commit ce99f7206c9105851d97202ed08c058af6f11ac4 upstream.
We need the total 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 is inaccurate or may not even be initialized.
Reported-by: Kevin Hao kexin.hao@windriver.com Fixes: 11abbc9f39e0 ("drm/tilcdc: Set framebuffer DMA address to HW only if CRTC is enabled") Signed-off-by: Jyri Sarha jsarha@ti.com Reviewed-by: Tomi Valkeinen tomi.valkeinen@ti.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c @@ -24,6 +24,7 @@ #include <linux/completion.h> #include <linux/dma-mapping.h> #include <linux/of_graph.h> +#include <linux/math64.h>
#include "tilcdc_drv.h" #include "tilcdc_regs.h" @@ -48,6 +49,7 @@ struct tilcdc_crtc { unsigned int lcd_fck_rate;
ktime_t last_vblank; + unsigned int hvtotal_us;
struct drm_framebuffer *curr_fb; struct drm_framebuffer *next_fb; @@ -292,6 +294,12 @@ static void tilcdc_crtc_set_clk(struct d LCDC_V2_CORE_CLK_EN); }
+uint tilcdc_mode_hvtotal(const struct drm_display_mode *mode) +{ + return (uint) div_u64(1000llu * mode->htotal * mode->vtotal, + mode->clock); +} + static void tilcdc_crtc_set_mode(struct drm_crtc *crtc) { struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc); @@ -459,6 +467,9 @@ static void tilcdc_crtc_set_mode(struct drm_framebuffer_reference(fb);
crtc->hwmode = crtc->state->adjusted_mode; + + tilcdc_crtc->hvtotal_us = + tilcdc_mode_hvtotal(&crtc->hwmode); }
static void tilcdc_crtc_enable(struct drm_crtc *crtc) @@ -648,7 +659,7 @@ int tilcdc_crtc_update_fb(struct drm_crt spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags);
next_vblank = ktime_add_us(tilcdc_crtc->last_vblank, - 1000000 / crtc->hwmode.vrefresh); + tilcdc_crtc->hvtotal_us); tdiff = ktime_to_us(ktime_sub(next_vblank, ktime_get()));
if (tdiff < TILCDC_VBLANK_SAFETY_THRESHOLD_US)