drm/imx: Add 8 pixel alignment fix

Some standard resolutions like 1366x768 do not work properly with
i.MX6 SoCs, since the horizontal resolution needs to be aligned
to 8 pixels (so 1360x768 or 1368x768 would work).

This patch allocates framebuffers allocated to 8 pixels. The extra
time required to send the extra pixels are removed from the blank
time. In order to expose the correct display size to userspace,
the stride is increased without increasing the width.

Without this patch systems with this display resolution hang
indefinitely during boot up.

Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20210428222953.235280-3-sebastian.reichel@collabora.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 15 insertions, 4 deletions

diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
index fc8f4834ed7b..9a7150ac34a6 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.c
+++ b/drivers/gpu/drm/imx/ipuv3-plane.c
@@ -30,6 +30,11 @@ to_ipu_plane_state(struct drm_plane_state *p)
 	return container_of(p, struct ipu_plane_state, base);
 }
 
+static unsigned int ipu_src_rect_width(const struct drm_plane_state *state)
+{
+	return ALIGN(drm_rect_width(&state->src) >> 16, 8);
+}
+
 static inline struct ipu_plane *to_ipu_plane(struct drm_plane *p)
 {
 	return container_of(p, struct ipu_plane, base);
@@ -440,6 +445,12 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
 	if (old_fb && fb->pitches[0] != old_fb->pitches[0])
 		crtc_state->mode_changed = true;
 
+	if (ALIGN(fb->width, 8) * fb->format->cpp[0] >
+	    fb->pitches[0] + fb->offsets[0]) {
+		dev_warn(dev, "pitch is not big enough for 8 pixels alignment");
+		return -EINVAL;
+	}
+
 	switch (fb->format->format) {
 	case DRM_FORMAT_YUV420:
 	case DRM_FORMAT_YVU420:
@@ -615,7 +626,7 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
 	if (ipu_state->use_pre) {
 		axi_id = ipu_chan_assign_axi_id(ipu_plane->dma);
 		ipu_prg_channel_configure(ipu_plane->ipu_ch, axi_id,
-					  drm_rect_width(&new_state->src) >> 16,
+					  ipu_src_rect_width(new_state),
 					  drm_rect_height(&new_state->src) >> 16,
 					  fb->pitches[0], fb->format->format,
 					  fb->modifier, &eba);
@@ -648,9 +659,9 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
 		break;
 	}
 
-	ipu_dmfc_config_wait4eot(ipu_plane->dmfc, drm_rect_width(dst));
+	ipu_dmfc_config_wait4eot(ipu_plane->dmfc, ALIGN(drm_rect_width(dst), 8));
 
-	width = drm_rect_width(&new_state->src) >> 16;
+	width = ipu_src_rect_width(new_state);
 	height = drm_rect_height(&new_state->src) >> 16;
 	info = drm_format_info(fb->format->format);
 	ipu_calculate_bursts(width, info->cpp[0], fb->pitches[0],
@@ -715,7 +726,7 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
 
 		ipu_cpmem_zero(ipu_plane->alpha_ch);
 		ipu_cpmem_set_resolution(ipu_plane->alpha_ch,
-					 drm_rect_width(&new_state->src) >> 16,
+					 ipu_src_rect_width(new_state),
 					 drm_rect_height(&new_state->src) >> 16);
 		ipu_cpmem_set_format_passthrough(ipu_plane->alpha_ch, 8);
 		ipu_cpmem_set_high_priority(ipu_plane->alpha_ch);