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>

4 files changed, 48 insertions, 6 deletions

diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c
index be6001d8c984..3709d343784a 100644
--- a/drivers/gpu/drm/imx/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/imx-drm-core.c
@@ -147,9 +147,26 @@ static const struct drm_ioctl_desc imx_drm_ioctls[] = {
 	/* none so far */
 };
 
+static int imx_drm_dumb_create(struct drm_file *file_priv,
+			       struct drm_device *drm,
+			       struct drm_mode_create_dumb *args)
+{
+	u32 width = args->width;
+	int ret;
+
+	args->width = ALIGN(width, 8);
+
+	ret = drm_gem_cma_dumb_create(file_priv, drm, args);
+	if (ret)
+		return ret;
+
+	args->width = width;
+	return ret;
+}
+
 static const struct drm_driver imx_drm_driver = {
 	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
-	DRM_GEM_CMA_DRIVER_OPS,
+	DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE(imx_drm_dumb_create),
 	.ioctls			= imx_drm_ioctls,
 	.num_ioctls		= ARRAY_SIZE(imx_drm_ioctls),
 	.fops			= &imx_drm_driver_fops,
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index ffdc492c5bc5..53132ddf9587 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -274,6 +274,11 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder,
 			 "%s: mode exceeds 85 MHz pixel clock\n", __func__);
 	}
 
+	if (!IS_ALIGNED(mode->hdisplay, 8)) {
+		dev_warn(ldb->dev,
+			 "%s: hdisplay does not align to 8 byte\n", __func__);
+	}
+
 	if (dual) {
 		serial_clk = 3500UL * mode->clock;
 		imx_ldb_set_clock(ldb, mux, 0, serial_clk, di_clk);
diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index e6431a227feb..9c8829f945b2 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -305,10 +305,19 @@ static void ipu_crtc_mode_set_nofb(struct drm_crtc *crtc)
 	sig_cfg.vsync_pin = imx_crtc_state->di_vsync_pin;
 
 	drm_display_mode_to_videomode(mode, &sig_cfg.mode);
+	if (!IS_ALIGNED(sig_cfg.mode.hactive, 8)) {
+		unsigned int new_hactive = ALIGN(sig_cfg.mode.hactive, 8);
+
+		dev_warn(ipu_crtc->dev, "8-pixel align hactive %d -> %d\n",
+			 sig_cfg.mode.hactive, new_hactive);
+
+		sig_cfg.mode.hfront_porch = new_hactive - sig_cfg.mode.hactive;
+		sig_cfg.mode.hactive = new_hactive;
+	}
 
 	ipu_dc_init_sync(ipu_crtc->dc, ipu_crtc->di,
 			 mode->flags & DRM_MODE_FLAG_INTERLACE,
-			 imx_crtc_state->bus_format, mode->hdisplay);
+			 imx_crtc_state->bus_format, sig_cfg.mode.hactive);
 	ipu_di_init_sync_panel(ipu_crtc->di, &sig_cfg);
 }
 
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);