<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/gpu/drm/sun4i, branch v5.4.64</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>drm: sun4i: hdmi: Fix inverted HPD result</title>
<updated>2020-07-29T08:18:32+00:00</updated>
<author>
<name>Chen-Yu Tsai</name>
<email>wens@csie.org</email>
</author>
<published>2020-07-11T01:10:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=a2cdb4ebd84e30c526adfce4c5409874783c63b1'/>
<id>a2cdb4ebd84e30c526adfce4c5409874783c63b1</id>
<content type='text'>
[ Upstream commit baa1841eb797eadce6c907bdaed7cd6f01815404 ]

When the extra HPD polling in sun4i_hdmi was removed, the result of
HPD was accidentally inverted.

Fix this by inverting the check.

Fixes: bda8eaa6dee7 ("drm: sun4i: hdmi: Remove extra HPD polling")
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Tested-by: Mans Rullgard &lt;mans@mansr.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200711011030.21997-1-wens@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit baa1841eb797eadce6c907bdaed7cd6f01815404 ]

When the extra HPD polling in sun4i_hdmi was removed, the result of
HPD was accidentally inverted.

Fix this by inverting the check.

Fixes: bda8eaa6dee7 ("drm: sun4i: hdmi: Remove extra HPD polling")
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Tested-by: Mans Rullgard &lt;mans@mansr.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200711011030.21997-1-wens@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: tcon: Separate quirks for tcon0 and tcon1 on A20</title>
<updated>2020-07-22T07:32:57+00:00</updated>
<author>
<name>Andrey Lebedev</name>
<email>andrey@lebedev.lt</email>
</author>
<published>2020-02-19T18:08:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=23a609417361875d72c0cc3399fe7b20428681b8'/>
<id>23a609417361875d72c0cc3399fe7b20428681b8</id>
<content type='text'>
[ Upstream commit cd0ecabdc953397ed0378022b3b90e0c0871c2eb ]

Timing controllers on A20 are not equivalent: tcon0 on A20 supports
LVDS output and tcon1 does not. Separate the capabilities by
introducing independent set of quirks for each of the tcons.

Signed-off-by: Andrey Lebedev &lt;andrey@lebedev.lt&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200219180858.4806-3-andrey.lebedev@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit cd0ecabdc953397ed0378022b3b90e0c0871c2eb ]

Timing controllers on A20 are not equivalent: tcon0 on A20 supports
LVDS output and tcon1 does not. Separate the capabilities by
introducing independent set of quirks for each of the tcons.

Signed-off-by: Andrey Lebedev &lt;andrey@lebedev.lt&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200219180858.4806-3-andrey.lebedev@gmail.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: sun4i: hdmi: Remove extra HPD polling</title>
<updated>2020-07-09T07:37:54+00:00</updated>
<author>
<name>Chen-Yu Tsai</name>
<email>wens@csie.org</email>
</author>
<published>2020-06-29T06:00:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=f795a88eade59463e842a506936003b5945e1db2'/>
<id>f795a88eade59463e842a506936003b5945e1db2</id>
<content type='text'>
[ Upstream commit bda8eaa6dee7525f4dac950810a85a88bf6c2ba0 ]

The HPD sense mechanism in Allwinner's old HDMI encoder hardware is more
or less an input-only GPIO. Other GPIO-based HPD implementations
directly return the current state, instead of polling for a specific
state and returning the other if that times out.

Remove the I/O polling from sun4i_hdmi_connector_detect() and directly
return a known state based on the current reading. This also gets rid
of excessive CPU usage by kworker as reported on Stack Exchange [1] and
Armbian forums [2].

 [1] https://superuser.com/questions/1515001/debian-10-buster-on-cubietruck-with-bug-in-sun4i-drm-hdmi
 [2] https://forum.armbian.com/topic/14282-headless-systems-and-sun4i_drm_hdmi-a10a20/

Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support")
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200629060032.24134-1-wens@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bda8eaa6dee7525f4dac950810a85a88bf6c2ba0 ]

The HPD sense mechanism in Allwinner's old HDMI encoder hardware is more
or less an input-only GPIO. Other GPIO-based HPD implementations
directly return the current state, instead of polling for a specific
state and returning the other if that times out.

Remove the I/O polling from sun4i_hdmi_connector_detect() and directly
return a known state based on the current reading. This also gets rid
of excessive CPU usage by kworker as reported on Stack Exchange [1] and
Armbian forums [2].

 [1] https://superuser.com/questions/1515001/debian-10-buster-on-cubietruck-with-bug-in-sun4i-drm-hdmi
 [2] https://forum.armbian.com/topic/14282-headless-systems-and-sun4i_drm_hdmi-a10a20/

Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support")
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200629060032.24134-1-wens@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: hdmi ddc clk: Fix size of m divider</title>
<updated>2020-06-24T15:50:43+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2020-04-13T09:54:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ab482b587207b1c39ca5cc23342937eb284291eb'/>
<id>ab482b587207b1c39ca5cc23342937eb284291eb</id>
<content type='text'>
[ Upstream commit 54e1e06bcf1cf6e7ac3f86daa5f7454add24b494 ]

m divider in DDC clock register is 4 bits wide. Fix that.

Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Reviewed-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200413095457.1176754-1-jernej.skrabec@siol.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 54e1e06bcf1cf6e7ac3f86daa5f7454add24b494 ]

m divider in DDC clock register is 4 bits wide. Fix that.

Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Reviewed-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200413095457.1176754-1-jernej.skrabec@siol.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sun6i: dsi: fix gcc-4.8</title>
<updated>2020-05-20T06:20:06+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2020-04-28T21:50:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e2824505a8132b0e6e0c3050bdccc07ff6185340'/>
<id>e2824505a8132b0e6e0c3050bdccc07ff6185340</id>
<content type='text'>
[ Upstream commit 3a3a71f97c30983f1627c2c550d43566e9b634d2 ]

Older compilers warn about initializers with incorrect curly
braces:

drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c: In function 'sun6i_dsi_encoder_enable':
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:720:8: error: missing braces around initializer [-Werror=missing-braces]
  union phy_configure_opts opts = { 0 };
        ^
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:720:8: error: (near initialization for 'opts.mipi_dphy') [-Werror=missing-braces]

Use the GNU empty initializer extension to avoid this.

Fixes: bb3b6fcb6849 ("sun6i: dsi: Convert to generic phy handling")
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200428215105.3928459-1-arnd@arndb.de
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 3a3a71f97c30983f1627c2c550d43566e9b634d2 ]

Older compilers warn about initializers with incorrect curly
braces:

drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c: In function 'sun6i_dsi_encoder_enable':
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:720:8: error: missing braces around initializer [-Werror=missing-braces]
  union phy_configure_opts opts = { 0 };
        ^
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c:720:8: error: (near initialization for 'opts.mipi_dphy') [-Werror=missing-braces]

Use the GNU empty initializer extension to avoid this.

Fixes: bb3b6fcb6849 ("sun6i: dsi: Convert to generic phy handling")
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200428215105.3928459-1-arnd@arndb.de
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: de2/de3: Remove unsupported VI layer formats</title>
<updated>2020-03-12T12:00:27+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2020-02-24T17:38:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=609b392e85230fe7b82f1ae0b4a34f47a7808eb8'/>
<id>609b392e85230fe7b82f1ae0b4a34f47a7808eb8</id>
<content type='text'>
commit a4769905f0ae32cae4f096f646ab03b8b4794c74 upstream.

YUV444 and YVU444 are planar formats, but HW format RGB888 is packed.
This means that those two mappings were never correct. Remove them.

Fixes: 60a3dcf96aa8 ("drm/sun4i: Add DE2 definitions for YUV formats")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-2-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a4769905f0ae32cae4f096f646ab03b8b4794c74 upstream.

YUV444 and YVU444 are planar formats, but HW format RGB888 is packed.
This means that those two mappings were never correct. Remove them.

Fixes: 60a3dcf96aa8 ("drm/sun4i: Add DE2 definitions for YUV formats")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-2-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: Fix DE2 VI layer format support</title>
<updated>2020-03-12T12:00:26+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2020-02-24T17:38:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=a49ddfae6c1a86983a3feec79b520e75eed9d5e9'/>
<id>a49ddfae6c1a86983a3feec79b520e75eed9d5e9</id>
<content type='text'>
commit 20896ef137340e9426cf322606f764452f5eb960 upstream.

DE2 VI layer doesn't support blending which means alpha channel is
ignored. Replace all formats with alpha with "don't care" (X) channel.

Fixes: 7480ba4d7571 ("drm/sun4i: Add support for DE2 VI planes")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-4-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 20896ef137340e9426cf322606f764452f5eb960 upstream.

DE2 VI layer doesn't support blending which means alpha channel is
ignored. Replace all formats with alpha with "don't care" (X) channel.

Fixes: 7480ba4d7571 ("drm/sun4i: Add support for DE2 VI planes")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-4-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: Add separate DE3 VI layer formats</title>
<updated>2020-03-12T12:00:26+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2020-02-24T17:38:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=dfe25f9a1c26d7c80a7777c4a32e7254eadbb21c'/>
<id>dfe25f9a1c26d7c80a7777c4a32e7254eadbb21c</id>
<content type='text'>
commit 169ca4b38932112e8b2ee8baef9cea44678625b3 upstream.

DE3 VI layers support alpha blending, but DE2 VI layers do not.
Additionally, DE3 VI layers support 10-bit RGB and YUV formats.

Make a separate list for DE3.

Fixes: c50519e6db4d ("drm/sun4i: Add basic support for DE3")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-3-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 169ca4b38932112e8b2ee8baef9cea44678625b3 upstream.

DE3 VI layers support alpha blending, but DE2 VI layers do not.
Additionally, DE3 VI layers support 10-bit RGB and YUV formats.

Make a separate list for DE3.

Fixes: c50519e6db4d ("drm/sun4i: Add basic support for DE3")
Acked-by: Maxime Ripard &lt;mripard@kernel.org&gt;
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-3-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "drm/sun4i: drv: Allow framebuffer modifiers in mode config"</title>
<updated>2020-02-19T18:53:09+00:00</updated>
<author>
<name>Jernej Skrabec</name>
<email>jernej.skrabec@siol.net</email>
</author>
<published>2020-01-26T06:59:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=0e365eafbcaa00645ab0469ac84d598f6bb4e03b'/>
<id>0e365eafbcaa00645ab0469ac84d598f6bb4e03b</id>
<content type='text'>
commit cf913e9683273f2640501094fa63a67e29f437b3 upstream.

This reverts commit 9db9c0cf5895e4ddde2814360cae7bea9282edd2.

Setting mode_config.allow_fb_modifiers manually is completely
unnecessary. It is set automatically by drm_universal_plane_init() based
on the fact if modifier list is provided or not. Even more, it breaks
DE2 and DE3 as they don't support any modifiers beside linear. Modifiers
aware applications can be confused by provided empty modifier list - at
least linear modifier should be included, but it's not for DE2 and DE3.

Fixes: 9db9c0cf5895 ("drm/sun4i: drv: Allow framebuffer modifiers in mode config")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200126065937.9564-1-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cf913e9683273f2640501094fa63a67e29f437b3 upstream.

This reverts commit 9db9c0cf5895e4ddde2814360cae7bea9282edd2.

Setting mode_config.allow_fb_modifiers manually is completely
unnecessary. It is set automatically by drm_universal_plane_init() based
on the fact if modifier list is provided or not. Even more, it breaks
DE2 and DE3 as they don't support any modifiers beside linear. Modifiers
aware applications can be confused by provided empty modifier list - at
least linear modifier should be included, but it's not for DE2 and DE3.

Fixes: 9db9c0cf5895 ("drm/sun4i: drv: Allow framebuffer modifiers in mode config")
Signed-off-by: Jernej Skrabec &lt;jernej.skrabec@siol.net&gt;
Reviewed-by: Paul Kocialkowski &lt;paul.kocialkowski@bootlin.com&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200126065937.9564-1-jernej.skrabec@siol.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>drm/sun4i: tcon: Set RGB DCLK min. divider based on hardware model</title>
<updated>2020-01-14T19:08:25+00:00</updated>
<author>
<name>Chen-Yu Tsai</name>
<email>wens@csie.org</email>
</author>
<published>2020-01-07T07:01:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c001b900caa6ddafd5becf09fef7614141cf583e'/>
<id>c001b900caa6ddafd5becf09fef7614141cf583e</id>
<content type='text'>
commit 4396393fb96449c56423fb4b351f76e45a6bcaf6 upstream.

In commit 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK
to 1.") it was assumed that all TCON variants support a minimum divider
of 1 if only DCLK was used.

However, the oldest generation of hardware only supports minimum divider
of 4 if only DCLK is used. If a divider of 1 was used on this old
hardware, some scrolling artifact would appear. A divider of 2 seemed
OK, but a divider of 3 had artifacts as well.

Set the minimum divider when outputing to parallel RGB based on the
hardware model, with a minimum of 4 for the oldest (A10/A10s/A13/A20)
hardware, and a minimum of 1 for the rest. A value is not set for the
TCON variants lacking channel 0.

This fixes the scrolling artifacts seen on my A13 tablet.

Fixes: 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK to 1.")
Cc: &lt;stable@vger.kernel.org&gt; # 5.4.x
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200107070113.28951-1-wens@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit 4396393fb96449c56423fb4b351f76e45a6bcaf6 upstream.

In commit 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK
to 1.") it was assumed that all TCON variants support a minimum divider
of 1 if only DCLK was used.

However, the oldest generation of hardware only supports minimum divider
of 4 if only DCLK is used. If a divider of 1 was used on this old
hardware, some scrolling artifact would appear. A divider of 2 seemed
OK, but a divider of 3 had artifacts as well.

Set the minimum divider when outputing to parallel RGB based on the
hardware model, with a minimum of 4 for the oldest (A10/A10s/A13/A20)
hardware, and a minimum of 1 for the rest. A value is not set for the
TCON variants lacking channel 0.

This fixes the scrolling artifacts seen on my A13 tablet.

Fixes: 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK to 1.")
Cc: &lt;stable@vger.kernel.org&gt; # 5.4.x
Signed-off-by: Chen-Yu Tsai &lt;wens@csie.org&gt;
Signed-off-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20200107070113.28951-1-wens@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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