[igt-dev] [PATCH 2/2] tests/fbdev: Add tests for read/write ops on framebuffer

[Thomas Zimmermann]

Read and write tests check the read and written buffer against the
content of the mapped framebuffer. Fbdev has some specific behavior
when reading/writing near the EOF, which the eof test checks.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 tests/fbdev.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/tests/fbdev.c b/tests/fbdev.c
index 11df954d..045b0874 100644
--- a/tests/fbdev.c
+++ b/tests/fbdev.c
@@ -25,6 +25,7 @@
 
 #include "igt.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <string.h>
 #include <sys/ioctl.h>
@@ -43,6 +44,7 @@ igt_main
 	struct fb_fix_screeninfo fix_info;
 	int fd = -1;
 	void *map = NULL;
+	void *buf = NULL;
 
 	/*
 	 * Should this test focus on the fbdev independent of any drm driver,
@@ -82,7 +84,85 @@ igt_main
 		memset(map, 0, fix_info.smem_len);
 	}
 
+	igt_subtest("read") {
+		ssize_t ret;
+		int cmp;
+
+		/* allocate two additional byte for eof test */
+		buf = malloc(fix_info.smem_len + 2);
+		igt_assert(buf);
+
+		/* framebuffer should be 0 from mmap test */
+		ret = pread(fd, buf, fix_info.smem_len, 0);
+		igt_require_f(ret == (ssize_t)fix_info.smem_len, "pread failed\n");
+		cmp = memcmp(map, buf, fix_info.smem_len);
+		igt_require_f(!cmp, "read buffer differs from mapped framebuffer for 0\n");
+
+		/* fill framebuffer with 0x55 and compare again */
+		memset(map, 0x55, fix_info.smem_len);
+		ret = pread(fd, buf, fix_info.smem_len, 0);
+		igt_require_f(ret == (ssize_t)fix_info.smem_len, "pread failed\n");
+		cmp = memcmp(map, buf, fix_info.smem_len);
+		igt_require_f(!cmp, "read buffer differs from mapped framebuffer for 0x55\n");
+	}
+
+	igt_subtest("write") {
+		ssize_t ret;
+		int cmp;
+
+		/* clear framebuffer and compare again */
+		memset(buf, 0, fix_info.smem_len);
+		ret = pwrite(fd, buf, fix_info.smem_len, 0);
+		igt_require_f(ret == (ssize_t)fix_info.smem_len, "pwrite failed\n");
+		cmp = memcmp(map, buf, fix_info.smem_len);
+		igt_require_f(!cmp, "write buffer differs from mapped framebuffer for 0\n");
+	}
+
+	igt_subtest("eof") {
+		unsigned long lastindex = fix_info.smem_len - 1;
+		unsigned char *maplast = &((unsigned char *)map)[lastindex];
+		unsigned char *buflast = &((unsigned char *)buf)[lastindex];
+		long long ret;
+
+		*buflast = 0x55;
+
+		/* write across EOF; set remaining bytes */
+		ret = (long long)pwrite(fd, buflast, 2, lastindex);
+		igt_require_f(ret == 1, "write crossed EOF, ret=%lld\n", ret);
+		igt_require_f(*maplast == *buflast, "write buffer differs from mapped framebuffer at final byte, "
+		                                    "maplast=%u buflast=%u\n", *maplast, *buflast);
+
+		/* write at EOF; get ENOSPC */
+		ret = (long long)pwrite(fd, &buflast[1], 1, lastindex + 1);
+		igt_require_f((ret == -1) && (errno == ENOSPC), "write at EOF, ret=%lld\n", ret);
+
+		*maplast = 0;
+
+		/* write final byte */
+		ret = (long long)pwrite(fd, buflast, 1, lastindex);
+		igt_require_f(ret == 1, "write before EOF, ret=%lld\n", ret);
+		igt_require_f(*maplast == *buflast, "write buffer differs from mapped framebuffer at final byte, "
+		                                    "maplast=%u buflast=%u\n", *maplast, *buflast);
+
+		/* write after EOF; get EFBIG */
+		ret = (long long)pwrite(fd, &buflast[2], 1, lastindex + 2);
+		igt_require_f((ret == -1) && (errno == EFBIG), "write after EOF, ret=%lld\n", ret);
+
+		*maplast = 0;
+
+		/* read across the EOF; get remaining bytes */
+		ret = (long long)pread(fd, buflast, 2, lastindex);
+		igt_require_f(ret == 1, "read before EOF\n");
+		igt_require_f(*maplast == *buflast, "read buffer differs from mapped framebuffer at final byte, "
+		                                    "maplast=%u buflast=%u\n", *maplast, *buflast);
+
+		/* read after EOF; get 0 */
+		ret = (long long)pread(fd, &buflast[1], 1, lastindex + 1);
+		igt_require_f(ret == 0, "read at EOF, ret=%lld\n", ret);
+	}
+
 	igt_fixture {
+		free(buf);
 		if (map && map != MAP_FAILED)
 			munmap(map, fix_info.smem_len);
 		close(fd);
-- 
2.29.0