On Tue, Apr 29, 2014 at 9:38 AM, Inki Dae <inki.dae at samsung.com> wrote:
> From: Akshu Agrawal <akshu.a at samsung.com>
>
> If any fimd channel was already active, initializing iommu will result
> in a PAGE FAULT (e.e. u-boot could have turned on the display and
> not disabled it before the kernel starts). This patch checks if any
> channel is active before initializing iommu and disables it.
>
> Changelog v2:
> - consider SoC without SHADOWCON register
>
> Signed-off-by: Akshu Agrawal <akshu.a at samsung.com>
> Signed-off-by: Prathyush K <prathyush.k at samsung.com>
> Signed-off-by: Inki Dae <inki.dae at samsung.com>
> ---
> drivers/gpu/drm/exynos/exynos_drm_fimd.c | 70
> +++++++++++++++++++++---------
> 1 file changed, 50 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> index 40fd6cc..ef21ce4 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> @@ -143,6 +143,48 @@ static inline struct fimd_driver_data
> *drm_fimd_get_driver_data(
> return (struct fimd_driver_data *)of_id->data;
> }
>
> +static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
> +{
> + struct fimd_context *ctx = mgr->ctx;
> +
> + if (ctx->suspended)
> + return;
> +
>
Hi Inki,
I think you need this to guarantee that the irq is actually enabled:
drm_vblank_get(ctx->drm_dev, ctx->pipe);
+ atomic_set(&ctx->wait_vsync_event, 1);
> +
> + /*
> + * wait for FIMD to signal VSYNC interrupt or return after
> + * timeout which is set to 50ms (refresh rate of 20).
> + */
> + if (!wait_event_timeout(ctx->wait_vsync_queue,
> + !atomic_read(&ctx->wait_vsync_event),
> + HZ/20))
> + DRM_DEBUG_KMS("vblank wait timed out.\n");
>
drm_vblank_put(ctx->drm_dev, ctx->pipe);
> +}
> +
> +
> +static void fimd_clear_channel(struct exynos_drm_manager *mgr)
> +{
> + struct fimd_context *ctx = mgr->ctx;
> + int win, ch_enabled = 0;
> +
> + DRM_DEBUG_KMS("%s\n", __FILE__);
> +
> + /* Check if any channel is enabled. */
> + for (win = 0; win < WINDOWS_NR; win++) {
> + u32 val = readl(ctx->regs + SHADOWCON);
> + if (val & SHADOWCON_CHx_ENABLE(win)) {
> + val &= ~SHADOWCON_CHx_ENABLE(win);
> + writel(val, ctx->regs + SHADOWCON);
> + ch_enabled = 1;
> + }
> + }
> +
> + /* Wait for vsync, as disable channel takes effect at next vsync */
> + if (ch_enabled)
> + fimd_wait_for_vblank(mgr);
> +}
> +
> static int fimd_mgr_initialize(struct exynos_drm_manager *mgr,
> struct drm_device *drm_dev, int pipe)
> {
> @@ -169,8 +211,15 @@ static int fimd_mgr_initialize(struct
> exynos_drm_manager *mgr,
> drm_dev->vblank_disable_allowed = true;
>
> /* attach this sub driver to iommu mapping if supported. */
> - if (is_drm_iommu_supported(ctx->drm_dev))
> + if (is_drm_iommu_supported(ctx->drm_dev)) {
> + /*
> + * If any channel is already active, iommu will throw
> + * a PAGE FAULT when enabled. So clear any channel if
> enabled.
> + */
> + if (ctx->driver_data->has_shadowcon)
> + fimd_clear_channel(mgr);
>
We already disable all overlays at the end of fimd_probe() by calling
fimd_clear_win().
Perhaps all that was missing was just waiting until the next vblank to
ensure that these clears have all completed?
Best Regards,
-Daniel
drm_iommu_attach_device(ctx->drm_dev, ctx->dev);
> + }
>
> return 0;
> }
> @@ -324,25 +373,6 @@ static void fimd_disable_vblank(struct
> exynos_drm_manager *mgr)
> }
> }
>
> -static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
> -{
> - struct fimd_context *ctx = mgr->ctx;
> -
> - if (ctx->suspended)
> - return;
> -
> - atomic_set(&ctx->wait_vsync_event, 1);
> -
> - /*
> - * wait for FIMD to signal VSYNC interrupt or return after
> - * timeout which is set to 50ms (refresh rate of 20).
> - */
> - if (!wait_event_timeout(ctx->wait_vsync_queue,
> - !atomic_read(&ctx->wait_vsync_event),
> - HZ/20))
> - DRM_DEBUG_KMS("vblank wait timed out.\n");
> -}
> -
> static void fimd_win_mode_set(struct exynos_drm_manager *mgr,
> struct exynos_drm_overlay *overlay)
> {
> --
> 1.7.9.5
>
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