From: Jagan Teki <jagan@amarulasolutions.com>
To: Maxime Ripard <maxime.ripard@bootlin.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Chen-Yu Tsai <wens@csie.org>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-sunxi@googlegroups.com,
Jagan Teki <jagan@amarulasolutions.com>,
Michael Trimarchi <michael@amarulasolutions.com>,
linux-amarula@amarulasolutions.com,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v9 1/5] drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflow
Date: Sun, 3 Mar 2019 23:05:23 +0530 [thread overview]
Message-ID: <20190303173527.31055-2-jagan@amarulasolutions.com> (raw)
In-Reply-To: <20190303173527.31055-1-jagan@amarulasolutions.com>
Loop N1 instruction delay for burst mode devices are computed
based on horizontal sync and porch timing values.
The current driver is using u16 type for computing this hsync_porch
value, which would failed to fit within the u16 type for large sync
and porch timings devices. This would result in hsync_porch overflow
and eventually computed wrong instruction delay value.
Example, timings, where it produces the overflow
{
.hdisplay = 1080,
.hsync_start = 1080 + 408,
.hsync_end = 1080 + 408 + 4,
.htotal = 1080 + 408 + 4 + 38,
}
It reproduces the desired delay value 65487 but the correct working
value should be 7.
So, Fix it by computing hsync_porch value separately with u32 type.
Fixes: 1c1a7aa3663c ("drm/sun4i: dsi: Add burst support")
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Merlijn Wajer <merlijn@wizzup.org>
---
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 6ff585055a07..465e7fc57899 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -457,8 +457,9 @@ static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi *dsi,
u16 delay = 50 - 1;
if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
- delay = (mode->htotal - mode->hdisplay) * 150;
- delay /= (mode->clock / 1000) * 8;
+ u32 hsync_porch = (mode->htotal - mode->hdisplay);
+
+ delay = ((hsync_porch * 150) / ((mode->clock / 1000) * 8));
delay -= 50;
}
--
2.18.0.321.gffc6fa0e3
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next prev parent reply other threads:[~2019-03-03 17:36 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-03 17:35 [PATCH v9 0/5] drm/sun4i: sun6i_mipi_dsi: Fixes/updates Jagan Teki
2019-03-03 17:35 ` Jagan Teki [this message]
2019-03-04 15:54 ` [PATCH v9 1/5] drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflow Maxime Ripard
2019-03-06 19:02 ` Jagan Teki
2019-03-03 17:35 ` [PATCH v9 5/5] drm/sun4i: sun6i_mipi_dsi: Simplify dsi setup timings code Jagan Teki
[not found] ` <20190303173527.31055-6-jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
2019-03-04 15:50 ` Maxime Ripard
2019-03-07 11:46 ` Jagan Teki
[not found] ` <20190303173527.31055-1-jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
2019-03-03 17:35 ` [PATCH v9 2/5] drm/sun4i: sun6i_mipi_dsi: Fix TCON DRQ set bits Jagan Teki
[not found] ` <20190303173527.31055-3-jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
2019-03-04 15:43 ` Maxime Ripard
2019-03-07 12:19 ` Jagan Teki
[not found] ` <CAMty3ZDWkLWgWhGWBjhXOsmAXzuGKGADAEhzB6gcL+jd7FRazQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-07 15:39 ` Maxime Ripard
2019-03-07 15:54 ` Jagan Teki
[not found] ` <CAMty3ZDyk60R0YCsBV6toz84CFjD0D6uWyLVhmp8PC+Mj8GJpQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-11 14:09 ` Maxime Ripard
2019-03-11 14:58 ` Jagan Teki
[not found] ` <CAMty3ZCABQ8Sa9+E_nznzMEYpvVm+KrnXDuEgt9qwue9t5Zs8g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-19 10:56 ` Maxime Ripard
2019-03-28 11:53 ` Jagan Teki
2019-04-02 14:47 ` Maxime Ripard
2019-03-03 17:35 ` [PATCH v9 3/5] drm/sun4i: sun6i_mipi_dsi: Support vblk timing for 4-lane devices Jagan Teki
[not found] ` <20190303173527.31055-4-jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
2019-03-04 15:49 ` Maxime Ripard
2019-03-07 16:03 ` Jagan Teki
[not found] ` <CAMty3ZBVh_PTYB-HmLCUuRsH+4NU=CaeXdKtNYqEDHHZuRGCvw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-11 14:04 ` Maxime Ripard
2019-03-11 14:33 ` Jagan Teki
2019-03-03 17:35 ` [PATCH v9 4/5] drm/sun4i: sun6i_mipi_dsi: Support DSI GENERIC_SHORT_WRITE_2 transfer Jagan Teki
2019-03-18 18:28 ` [PATCH v9 0/5] drm/sun4i: sun6i_mipi_dsi: Fixes/updates Jagan Teki
[not found] ` <CAMty3ZAGvCOuqcTUozBm-uR4z=jR18bfOSyN5=jfT85HGWR_1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-19 10:58 ` Maxime Ripard
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