From: Dom Cobley popcornmix@gmail.com
Experimentally have found PV on hvs4 reports fifo full error with expected settings and does not with one less
This appears as: [drm:drm_atomic_helper_wait_for_flip_done] *ERROR* [CRTC:82:crtc-3] flip_done timed out
with bit 10 of PV_STAT set "HVS driving pixels when the PV FIFO is full"
Fixes: c8b75bca92cb ("drm/vc4: Add KMS support for Raspberry Pi.") Signed-off-by: Dom Cobley popcornmix@gmail.com Signed-off-by: Maxime Ripard maxime@cerno.tech --- drivers/gpu/drm/vc4/vc4_crtc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c index 269390bc586e..76657dcdf9b0 100644 --- a/drivers/gpu/drm/vc4/vc4_crtc.c +++ b/drivers/gpu/drm/vc4/vc4_crtc.c @@ -210,6 +210,7 @@ static u32 vc4_get_fifo_full_level(struct vc4_crtc *vc4_crtc, u32 format) { const struct vc4_crtc_data *crtc_data = vc4_crtc_to_vc4_crtc_data(vc4_crtc); const struct vc4_pv_data *pv_data = vc4_crtc_to_vc4_pv_data(vc4_crtc); + struct vc4_dev *vc4 = to_vc4_dev(vc4_crtc->base.dev); u32 fifo_len_bytes = pv_data->fifo_depth;
/* @@ -238,6 +239,22 @@ static u32 vc4_get_fifo_full_level(struct vc4_crtc *vc4_crtc, u32 format) if (crtc_data->hvs_output == 5) return 32;
+ /* + * It looks like in some situations, we will overflow + * the PixelValve FIFO (with the bit 10 of PV stat being + * set) and stall the HVS / PV, eventually resulting in + * a page flip timeout. + * + * Displaying the video overlay during a playback with + * Kodi on an RPi3 seems to be a great solution with a + * failure rate around 50%. + * + * Removing 1 from the FIFO full level however + * seems to completely remove that issue. + */ + if (!vc4->hvs->hvs5) + return fifo_len_bytes - 3 * HVS_FIFO_LATENCY_PIX - 1; + return fifo_len_bytes - 3 * HVS_FIFO_LATENCY_PIX; } }