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: michael@amarulasolutions.com, linux-amarula@amarulasolutions.com, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, Jagan Teki <jagan@amarulasolutions.com> Subject: [PATCH v10 1/2] drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflow Date: Mon, 13 May 2019 00:11:26 +0530 [thread overview] Message-ID: <20190512184128.13720-2-jagan@amarulasolutions.com> (raw) In-Reply-To: <20190512184128.13720-1-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> --- 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..bfa7e2b146df 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) * 150; + + delay = (hsync_porch / ((mode->clock / 1000) * 8)); delay -= 50; } -- 2.18.0.321.gffc6fa0e3
WARNING: multiple messages have this Message-ID (diff)
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@amarulasolutions.com, linux-amarula@amarulasolutions.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH v10 1/2] drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflow Date: Mon, 13 May 2019 00:11:26 +0530 [thread overview] Message-ID: <20190512184128.13720-2-jagan@amarulasolutions.com> (raw) In-Reply-To: <20190512184128.13720-1-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> --- 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..bfa7e2b146df 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) * 150; + + delay = (hsync_porch / ((mode->clock / 1000) * 8)); delay -= 50; } -- 2.18.0.321.gffc6fa0e3 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-05-12 18:42 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-12 18:41 [PATCH v10 0/2] drm/sun4i: sun6i_mipi_dsi: Fixes/updates Jagan Teki 2019-05-12 18:41 ` Jagan Teki 2019-05-12 18:41 ` Jagan Teki 2019-05-12 18:41 ` Jagan Teki [this message] 2019-05-12 18:41 ` [PATCH v10 1/2] drm/sun4i: sun6i_mipi_dsi: Fix hsync_porch overflow Jagan Teki 2019-05-12 18:41 ` [PATCH v10 2/2] drm/sun4i: sun6i_mipi_dsi: Support DSI GENERIC_SHORT_WRITE_2 transfer Jagan Teki 2019-05-12 18:41 ` Jagan Teki 2019-05-12 18:41 ` Jagan Teki 2019-05-16 9:11 ` [PATCH v10 0/2] drm/sun4i: sun6i_mipi_dsi: Fixes/updates Maxime Ripard 2019-05-16 9:11 ` Maxime Ripard 2019-05-16 9:11 ` Maxime Ripard
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