Commit 487778f8 authored by CK Hu's avatar CK Hu Committed by Chun-Kuang Hu
Browse files

drm/mediatek: dsi: Modify horizontal front/back porch byte formula 



In the patch to be fixed, horizontal_backporch_byte become too large
for some panel, so roll back that patch. For small hfp or hbp panel,
using vm->hfront_porch + vm->hback_porch to calculate
horizontal_backporch_byte would make it negtive, so
use horizontal_backporch_byte itself to make it positive.

Fixes: 35bf948f ("drm/mediatek: dsi: Fix scrolling of panel with small hfp or hbp")

Signed-off-by: default avatarCK Hu <ck.hu@mediatek.com>
Signed-off-by: default avatarChun-Kuang Hu <chunkuang.hu@kernel.org>
Tested-by: default avatarBilal Wasim <bilal.wasim@imgtec.com>
parent 46b97aed

drivers/gpu/drm/mediatek/mtk_dsi.c

+22 −39
Original line number Diff line number Diff line
@@ -444,7 +444,10 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi) 
	u32 horizontal_sync_active_byte;

	u32 horizontal_backporch_byte;

	u32 horizontal_frontporch_byte;

	u32 horizontal_front_back_byte;

	u32 data_phy_cycles_byte;

	u32 dsi_tmp_buf_bpp, data_phy_cycles;

	u32 delta;

	struct mtk_phy_timing *timing = &dsi->phy_timing;



	struct videomode *vm = &dsi->vm;
@@ -466,50 +469,30 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi) 
	horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);



	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)

		horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;

		horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp - 10;

	else

		horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *

					    dsi_tmp_buf_bpp;

					    dsi_tmp_buf_bpp - 10;



	data_phy_cycles = timing->lpx + timing->da_hs_prepare +

			  timing->da_hs_zero + timing->da_hs_exit;



	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {

		if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >

		    data_phy_cycles * dsi->lanes + 18) {

			horizontal_frontporch_byte =

				vm->hfront_porch * dsi_tmp_buf_bpp -

				(data_phy_cycles * dsi->lanes + 18) *

				vm->hfront_porch /

				(vm->hfront_porch + vm->hback_porch);



			horizontal_backporch_byte =

				horizontal_backporch_byte -

				(data_phy_cycles * dsi->lanes + 18) *

				vm->hback_porch /

				(vm->hfront_porch + vm->hback_porch);

		} else {

			DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");

			horizontal_frontporch_byte = vm->hfront_porch *

						     dsi_tmp_buf_bpp;

		}

	} else {

		if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >

		    data_phy_cycles * dsi->lanes + 12) {

			horizontal_frontporch_byte =

				vm->hfront_porch * dsi_tmp_buf_bpp -

				(data_phy_cycles * dsi->lanes + 12) *

				vm->hfront_porch /

				(vm->hfront_porch + vm->hback_porch);

			horizontal_backporch_byte = horizontal_backporch_byte -

				(data_phy_cycles * dsi->lanes + 12) *

				vm->hback_porch /

				(vm->hfront_porch + vm->hback_porch);

			  timing->da_hs_zero + timing->da_hs_exit + 3;



	delta = dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST ? 18 : 12;



	horizontal_frontporch_byte = vm->hfront_porch * dsi_tmp_buf_bpp;

	horizontal_front_back_byte = horizontal_frontporch_byte + horizontal_backporch_byte;

	data_phy_cycles_byte = data_phy_cycles * dsi->lanes + delta;



	if (horizontal_front_back_byte > data_phy_cycles_byte) {

		horizontal_frontporch_byte -= data_phy_cycles_byte *

					      horizontal_frontporch_byte /

					      horizontal_front_back_byte;



		horizontal_backporch_byte -= data_phy_cycles_byte *

					     horizontal_backporch_byte /

					     horizontal_front_back_byte;

	} else {

			DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");

			horizontal_frontporch_byte = vm->hfront_porch *

						     dsi_tmp_buf_bpp;

		}

		DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");

	}



	writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);

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