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* [PATCH] drm: mediatek: mtk_dsi: Fix NO_EOT_PACKET settings/handling
@ 2023-05-23 10:42 AngeloGioacchino Del Regno
  2023-06-23  9:47 ` AngeloGioacchino Del Regno
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: AngeloGioacchino Del Regno @ 2023-05-23 10:42 UTC (permalink / raw)
  To: chunkuang.hu
  Cc: p.zabel, airlied, daniel, matthias.bgg,
	angelogioacchino.delregno, jitao.shi, ck.hu, shaoming.chen,
	yt.shen, dri-devel, linux-mediatek, linux-kernel,
	linux-arm-kernel

Due to the initial confusion about MIPI_DSI_MODE_EOT_PACKET, properly
renamed to MIPI_DSI_MODE_NO_EOT_PACKET, reflecting its actual meaning,
both the DSI_TXRX_CON register setting for bit (HSTX_)DIS_EOT and the
later calculation for horizontal sync-active (HSA), back (HBP) and
front (HFP) porches got incorrect due to the logic being inverted.

This means that a number of settings were wrong because....:
 - DSI_TXRX_CON register setting: bit (HSTX_)DIS_EOT should be
   set in order to disable the End of Transmission packet;
 - Horizontal Sync and Back/Front porches: The delta used to
   calculate all of HSA, HBP and HFP should account for the
   additional EOT packet.

Before this change...
 - Bit (HSTX_)DIS_EOT was being set when EOT packet was enabled;
 - For HSA/HBP/HFP delta... all three were wrong, as words were
   added when EOT disabled, instead of when EOT packet enabled!

Invert the logic around flag MIPI_DSI_MODE_NO_EOT_PACKET in the
MediaTek DSI driver to fix the aforementioned issues.

Fixes: 8b2b99fd7931 ("drm/mediatek: dsi: Fine tune the line time caused by EOTp")
Fixes: 2d52bfba09d1 ("drm/mediatek: add non-continuous clock mode and EOT packet control")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 7d5250351193..b0ab38e59db9 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -407,7 +407,7 @@ static void mtk_dsi_rxtx_control(struct mtk_dsi *dsi)
 	if (dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
 		tmp_reg |= HSTX_CKLP_EN;
 
-	if (!(dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET))
+	if (dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET)
 		tmp_reg |= DIS_EOT;
 
 	writel(tmp_reg, dsi->regs + DSI_TXRX_CTRL);
@@ -484,7 +484,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 			  timing->da_hs_zero + timing->da_hs_exit + 3;
 
 	delta = dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST ? 18 : 12;
-	delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 2 : 0;
+	delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 0 : 2;
 
 	horizontal_frontporch_byte = vm->hfront_porch * dsi_tmp_buf_bpp;
 	horizontal_front_back_byte = horizontal_frontporch_byte + horizontal_backporch_byte;
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2023-10-18 13:25 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-23 10:42 [PATCH] drm: mediatek: mtk_dsi: Fix NO_EOT_PACKET settings/handling AngeloGioacchino Del Regno
2023-06-23  9:47 ` AngeloGioacchino Del Regno
2023-06-23 11:29   ` Alexandre Mergnat
2023-07-19  7:39     ` AngeloGioacchino Del Regno
2023-07-19 15:25 ` Chun-Kuang Hu
2023-09-15 10:11 ` Michael Walle
2023-10-18 10:21   ` AngeloGioacchino Del Regno
2023-10-18 13:24     ` Chun-Kuang Hu

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