[PATCH v6 06/14] drm/mediatek: Turn off the layers with zero width or height

From: Shawn Sung
Date: Fri Mar 22 2024 - 01:28:59 EST


From: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>

We found that IGT (Intel GPU Tool) will try to commit layers with
zero width or height and lead to undefined behaviors in hardware.
Disable the layers in such a situation.

Fixes: 777b7bc86a0a ("UPSTREAM: drm/mediatek: Add ovl_adaptor support for MT8195")
Fixes: fa97fe71f6f9 ("UPSTREAM: drm/mediatek: Add ETHDR support for MT8195")

Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c | 2 +-
drivers/gpu/drm/mediatek/mtk_ethdr.c | 7 ++++++-
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
index 4fbf61c6b5423..494f7bf4a7881 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
@@ -158,7 +158,7 @@ void mtk_ovl_adaptor_layer_config(struct device *dev, unsigned int idx,
merge = ovl_adaptor->ovl_adaptor_comp[OVL_ADAPTOR_MERGE0 + idx];
ethdr = ovl_adaptor->ovl_adaptor_comp[OVL_ADAPTOR_ETHDR0];

- if (!pending->enable) {
+ if (!pending->enable || !pending->width || !pending->height) {
mtk_merge_stop_cmdq(merge, cmdq_pkt);
mtk_mdp_rdma_stop(rdma_l, cmdq_pkt);
mtk_mdp_rdma_stop(rdma_r, cmdq_pkt);
diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index ac4132210585e..6bf398850e85f 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -160,7 +160,12 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
if (idx >= 4)
return;

- if (!pending->enable) {
+ if (!pending->enable || !pending->width || !pending->height) {
+ /*
+ * instead of disabling layer with MIX_SRC_CON directly
+ * set the size to 0 to avoid screen shift due to mixer
+ * mode switch (hardware behavior)
+ */
mtk_ddp_write(cmdq_pkt, 0, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_SIZE(idx));
return;
}
--
2.18.0