2016-11-16 13:41 GMT+01:00 Jyri Sarha <jsarha@xxxxxx>:
> Revision 1 LCDC support also sync lost errors and can benefit from
> sync lost recovery routine.
>
Hi Jyri,
I think I found the issue with this patch. Please see below.
> Signed-off-by: Jyri Sarha <jsarha@xxxxxx>
> ---
> drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 39 ++++++++++++++++++------------------
> drivers/gpu/drm/tilcdc/tilcdc_regs.h | 1 +
> 2 files changed, 21 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> index c787349..dfe5796 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> @@ -113,8 +113,8 @@ static void tilcdc_crtc_enable_irqs(struct drm_device *dev)
>
> if (priv->rev == 1) {
> tilcdc_set(dev, LCDC_RASTER_CTRL_REG,
> - LCDC_V1_UNDERFLOW_INT_ENA);
> - tilcdc_set(dev, LCDC_DMA_CTRL_REG,
> + LCDC_V1_UNDERFLOW_INT_ENA |
> + LCDC_V1_SYNC_LOST_ENA |
> LCDC_V1_END_OF_FRAME_INT_ENA);
> } else {
> tilcdc_write(dev, LCDC_INT_ENABLE_SET_REG,
> @@ -131,8 +131,9 @@ static void tilcdc_crtc_disable_irqs(struct drm_device *dev)
> /* disable irqs that we might have enabled: */
> if (priv->rev == 1) {
> tilcdc_clear(dev, LCDC_RASTER_CTRL_REG,
> - LCDC_V1_UNDERFLOW_INT_ENA | LCDC_V1_PL_INT_ENA);
> - tilcdc_clear(dev, LCDC_DMA_CTRL_REG,
> + LCDC_V1_UNDERFLOW_INT_ENA |
> + LCDC_V1_PL_INT_ENA |
> + LCDC_V1_SYNC_LOST_ENA |
> LCDC_V1_END_OF_FRAME_INT_ENA);
> } else {
> tilcdc_write(dev, LCDC_INT_ENABLE_CLR_REG,
This is what breaks the driver. The END_OF_FRAME interrupt is enabled
by writing to the LCD DMA control register on rev 1, not LCDC RASTER
control. It should be left as it is - you only need to enable the
SYNC_LOST interrupt.
Hint: maybe call it LCDC_V1_SYNC_LOST_INT_ENA?
> @@ -845,6 +846,21 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
> dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underflow",
> __func__, stat);
>
> + if (stat & LCDC_SYNC_LOST) {
> + dev_err_ratelimited(dev->dev, "%s(0x%08x): Sync lost",
> + __func__, stat);
> + tilcdc_crtc->frame_intact = false;
> + if (tilcdc_crtc->sync_lost_count++ >
> + SYNC_LOST_COUNT_LIMIT) {
> + dev_err(dev->dev, "%s(0x%08x): Sync lost flood detected, recovering", __func__, stat);
> + queue_work(system_wq,
> + &tilcdc_crtc->recover_work);
> + tilcdc_write(dev, LCDC_INT_ENABLE_CLR_REG,
> + LCDC_SYNC_LOST);
> + tilcdc_crtc->sync_lost_count = 0;
> + }
> + }
The SYNC_LOST bit still needs clearing here - otherwise the flood
never stops even after recovery work completes.
Thanks,
Bartosz Golaszewski
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