linux-kernel - Re: [PATCH 2/3] drm/nouveau/kms/nv50-: Report max cursor size to userspace

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Message-ID: <YDYXiTm7MDXgYT7H@pflmari>
Date:   Wed, 24 Feb 2021 10:08:25 +0100
From:   Alex Riesen <alexander.riesen@...itec.com>
To:     Ilia Mirkin <imirkin@...m.mit.edu>
Cc:     Lyude Paul <lyude@...hat.com>,
        Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@...el.com>,
        David Airlie <airlied@...ux.ie>,
        nouveau <nouveau@...ts.freedesktop.org>,
        James Jones <jajones@...dia.com>,
        LKML <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Jeremy Cline <jcline@...hat.com>,
        Ben Skeggs <bskeggs@...hat.com>,
        Dave Airlie <airlied@...hat.com>
Subject: Re: [PATCH 2/3] drm/nouveau/kms/nv50-: Report max cursor size to
 userspace

Ilia Mirkin, Tue, Feb 23, 2021 19:13:59 +0100:
> On Tue, Feb 23, 2021 at 11:23 AM Alex Riesen <alexander.riesen@...itec.com> wrote:
> >
> >     $ xrandr  --listproviders
> >     Providers: number : 1
> >     Provider 0: id: 0x68 cap: 0x7, Source Output, Sink Output, Source Offload crtcs: 4 outputs: 5 associated providers: 0 name:nouveau
> >
> > And yes, the cursor looks good in v5.11 even without reverting the commit.
> 
> FWIW it's not immediately apparent to me what grave error modesetting
> is committing in setting the cursor. The logic looks perfectly
> reasonable. It's not trying to be fancy with rendering the cursor/etc.
> 
> The one thing is that it's using drmModeSetCursor2 which sets the
> hotspot at the same time. But internally inside nouveau I think it
> should work out to the same thing. Perhaps setting the hotspot, or
> something in that path, doesn't quite work for 256x256? [Again, no
> clue what that might be.]
> 
> It might also be worthwhile just testing if the 256x256 cursor works
> quite the way one would want. If you're interested, grab libdrm,
> there's a test called 'modetest', which has an option to enable a
> moving cursor (-c iirc). It's hard-coded to 64x64, so you'll have to
> modify it there too (and probably change the pattern from plain gray
> to any one of the other ones).

I am interested, so I did.

If I start the test without X running, the sprite of 256x256 cursor always
contained horizontal lines across it, both with commit reverted and vanilla
v5.11. Similarly, the 64x64 cursor has no lines across it in both kernels.

The test does not seem to work at all if there is an X server running (using
modesetting driver): modetest complained about permission denied to set the
mode, and just sits there, drawing nothing on the displays.
So I could not run the test in the environment of original problem.
Am I starting it correctly? Is the change in modetest.c correct?

    $ ./modetest -c |grep '^[0-9]\|preferred'
    85	86	connected	LVDS-1         	340x190		13	86
      #0 1920x1080 60.01 1920 2010 2070 2226 1080 1086 1095 1142 152540 flags: phsync, nvsync; type: preferred, driver
    87	89	connected	DP-1           	470x300		18	88, 89
      #0 1680x1050 59.88 1680 1728 1760 1840 1050 1053 1059 1080 119000 flags: phsync, nvsync; type: preferred, driver
    90	0	disconnected	DP-2           	0x0		0	91, 92
    93	95	connected	DP-3           	520x320		10	94, 95
      #0 1920x1200 59.95 1920 1968 2000 2080 1200 1203 1209 1235 154000 flags: phsync, nvsync; type: preferred, driver
    96	0	disconnected	VGA-1          	0x0		0	97

    $ ./modetest -s 85:1920x1080 -s 93:1920x1200 -s 87:1680x1050  -C
    trying to open device 'i915'...failed
    trying to open device 'amdgpu'...failed
    trying to open device 'radeon'...failed
    trying to open device 'nouveau'...done
    setting mode 1920x1080-60.01Hz on connectors 85, crtc 50
    starting cursor

    cursor stopped

This is the change on top of 1225171b (master):

diff --git a/tests/modetest/modetest.c b/tests/modetest/modetest.c
index fc75383a..cdba7b4e 100644
--- a/tests/modetest/modetest.c
+++ b/tests/modetest/modetest.c
@@ -1730,14 +1730,14 @@ static void set_cursors(struct device *dev, struct pipe_arg *pipes, unsigned int
 	int ret;
 
 	/* maybe make cursor width/height configurable some day */
-	uint32_t cw = 64;
-	uint32_t ch = 64;
+	uint32_t cw = 256;
+	uint32_t ch = 256;
 
 	/* create cursor bo.. just using PATTERN_PLAIN as it has
 	 * translucent alpha
 	 */
 	bo = bo_create(dev->fd, DRM_FORMAT_ARGB8888, cw, ch, handles, pitches,
-		       offsets, UTIL_PATTERN_PLAIN);
+		       offsets, UTIL_PATTERN_SMPTE);
 	if (bo == NULL)
 		return;