[Bug 106233] [CI] igt at kms_cursor_legacy@cursor-vs-flip - Failed assertion: igt_ioctl((fd), ((((2U|1U) << (((0+8)+8)+14)) | ((('d')) << (0+8)) | (((0xB2)) << 0) | ...

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=106233

Matt Roper <matthew.d.roper at intel.com> changed:

           What    |Removed                     |Added
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                 CC|                            |matthew.d.roper at intel.com

--- Comment #7 from Matt Roper <matthew.d.roper at intel.com> ---
The failures here are because the DRM_IOCTL_MODE_CURSOR is being rejected by
the kernel because the pipe C cursor is straddling the left edge of the CRTC. 
Although that would usually okay (planes will be clipped if partially
offscreen), this causes hardware failures on CHV pipe C so we prohibit it in
that specific case.

Interestingly, I don't see anywhere in this test where we actually try to
position the cursor partially offscreen.  Also, positioning the cursor
partially offscreen should fail every time, whereas the behavior here seems
random (but only in the 'varying size' subtests).  There may be a bug in the
test somewhere (e.g., a buffer overflow or uninitialized field that results in
different random/wrong values being used as the cursor x coordinate) or there
may be a kernel bug causing us to corrupt the cursor's coordinates when we're
changing the cursor size.

The next step for debugging would probably be to check and see what coordinates
actually are being requested in the cases where this fails so that we can
figure out if we have a consistent logic error somewhere or whether there's
some random memory corruption going on (either in the test or in the driver).

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