[igt-dev] [PATCH v6 6/8] tests/fbdev: Add tests for unaligned writes on framebuffer memory

[Chris Wilson]

Quoting Thomas Zimmermann (2020-11-20 10:52:15)
> The tests for unaligned writes start and stop writing within pages.
> 
> v6:
>         * remove test from fast-feedback.testlist
> v4:
>         * replace igt_require() by igt_assert() in "unaligned-write" (Petri)
>         * clarify error message about framebuffer size (Petri)
>         * add unaligned-write test to CI
> v3:
>         * put igt_describe() before igt_subtest() (Petri)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
>  tests/fbdev.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/tests/fbdev.c b/tests/fbdev.c
> index 23ff146c..c4cb357f 100644
> --- a/tests/fbdev.c
> +++ b/tests/fbdev.c
> @@ -155,6 +155,35 @@ static void framebuffer_tests(int fd)
>                 igt_assert_f(!cmp, "write buffer differs from mapped framebuffer for 0\n");
>         }
>  
> +       igt_describe("Check write operations on unaligned locations in framebuffer memory");
> +       igt_subtest("unaligned-write") {
> +               off_t off;
> +               size_t len;
> +               ssize_t ret;
> +               const unsigned char *pos;
> +
> +               off = pagesize + (pagesize >> 2); // 1.25 * pagesize
> +               len = (pagesize << 2) + (pagesize >> 1); // 4.5 * pagesize
> +               igt_require_f((off + len) < fix_info.smem_len, "framebuffer too small to test\n");
> +
> +               /* read at unaligned location and compare */
> +               memset(map, 0xff, fix_info.smem_len);
> +               memset(buf, 0, fix_info.smem_len);
> +               memset(&buf[off], 0x55, len);
> +               ret = pwrite(fd, &buf[off], len, off);
> +               igt_assert_f(ret == (ssize_t)len, "pwrite failed, ret=%zd\n", ret);
> +               pos = memchr(map, 0x55, fix_info.smem_len);
> +               igt_assert_f(pos, "0x55 not found within framebuffer\n");
> +               igt_assert_f(pos == &map[off], "0x55 found at pos %zu, expected %lld\n",
> +                            pos - map, (long long)off);
> +               pos = memchr(&map[off], 0xff, fix_info.smem_len - off);
> +               igt_assert_f(pos, "0xff not found within framebuffer\n");
> +               igt_assert_f(pos == &map[off + len], "0xff found at pos %zu, expected %lld\n",
> +                            pos - map, (long long)(off + len));

> +               pos = memchr(&map[off + len], 0x55, fix_info.smem_len - off + len);

Spotted this typo in the unaligned read/write, should be
	smem_len - (off + len)

Applied some minor whitespace changes, the goal is to follow the kernel
coding style (so that we don't have to keep on switching styles :), and
that also allows us to use the same gcc-isms as we expect to find in the
kernel.

Series is
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
and pushed.
-Chris