[Intel-gfx] [PATCH igt] lib: add igt_debugfs_read()

Daniel Vetter daniel at ffwll.ch
Tue Jul 21 10:43:39 PDT 2015


On Tue, Jul 21, 2015 at 02:08:23PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> A helpful function for when you want to read a whole debugfs file to a
> string and don't want to worry about opening and closing file
> descriptors and asserting buffer sizes.
> 
> We've been using this already for kms_frontbuffer_tracking and
> kms_fbcon_fbt, so the only test with new code here is kms_fbc_crc.
> 
> Also notice that for kms_fbc_crc we had to increase the buffer size
> since the file can sometimes be bigger than 64 bytes - depending on
> the reason why FBC is disabled.
> 
> Of course, there are probably many other programs we can patch, but
> I'm not doing this now.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  lib/igt_debugfs.c                | 27 +++++++++++++++++++++++++++
>  lib/igt_debugfs.h                |  1 +
>  tests/kms_fbc_crc.c              | 18 ++++--------------
>  tests/kms_fbcon_fbt.c            | 25 ++++---------------------
>  tests/kms_frontbuffer_tracking.c | 33 ++++++++-------------------------
>  5 files changed, 44 insertions(+), 60 deletions(-)
> 
> diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
> index a2c6fe2..bc1bb05 100644
> --- a/lib/igt_debugfs.c
> +++ b/lib/igt_debugfs.c
> @@ -185,6 +185,33 @@ FILE *igt_debugfs_fopen(const char *filename,
>  	return fopen(buf, mode);
>  }
>  
> +/**
> + * igt_debugfs_read:
> + * @filename: file name
> + * @buf: buffer where the contents will be stored, allocated by the caller
> + * @buf_size: size of the buffer
> + *
> + * This function opens the debugfs file, reads it, stores the content in the
> + * provided buffer, then closes the file. Users should make sure that the buffer
> + * provided is big enough to fit the whole file, plus one byte.

Hm if we want a helper function to slurp in an entire file I'd go with one
that mallocs a suitably big buffer. That means more free calls, but imo
that's less onerous than getting buffer sizes right (well at least for a
library function).

If you don't like that I'd rename this with a __ prefix and do a

#define igt_debugfs_read(file, buf) \
	__igt_debugfs_read((file), (buf), sizeof(buf))

That way it's fairly impossible to get the static sizing wrong at least.
-Daniel

> + */
> +void igt_debugfs_read(const char *filename, char *buf, int buf_size)
> +{
> +	FILE *file;
> +	size_t n_read;
> +
> +	file = igt_debugfs_fopen(filename, "r");
> +	igt_assert(file);
> +
> +	n_read = fread(buf, 1, buf_size - 1, file);
> +	igt_assert(n_read > 0);
> +	igt_assert(feof(file));
> +
> +	buf[n_read] = '\0';
> +
> +	igt_assert(fclose(file) == 0);
> +}
> +
>  /*
>   * Pipe CRC
>   */
> diff --git a/lib/igt_debugfs.h b/lib/igt_debugfs.h
> index ece7148..a0bb75e 100644
> --- a/lib/igt_debugfs.h
> +++ b/lib/igt_debugfs.h
> @@ -34,6 +34,7 @@ enum pipe;
>  int igt_debugfs_open(const char *filename, int mode);
>  FILE *igt_debugfs_fopen(const char *filename,
>  			const char *mode);
> +void igt_debugfs_read(const char *filename, char *buf, int buf_size);
>  
>  /*
>   * Pipe CRC
> diff --git a/tests/kms_fbc_crc.c b/tests/kms_fbc_crc.c
> index f2a86a6..28cc165 100644
> --- a/tests/kms_fbc_crc.c
> +++ b/tests/kms_fbc_crc.c
> @@ -215,14 +215,9 @@ static void fill_mmap_gtt(data_t *data, uint32_t handle, unsigned char color)
>  
>  static bool fbc_enabled(data_t *data)
>  {
> -	FILE *status;
> -	char str[64] = {};
> +	char str[128] = {};
>  
> -	status = igt_debugfs_fopen("i915_fbc_status", "r");
> -	igt_assert(status);
> -
> -	igt_assert(fread(str, 1, sizeof(str) - 1, status) > 0);
> -	fclose(status);
> +	igt_debugfs_read("i915_fbc_status", str, sizeof(str));
>  	return strstr(str, "FBC enabled") != NULL;
>  }
>  
> @@ -544,8 +539,7 @@ igt_main
>  	igt_skip_on_simulation();
>  
>  	igt_fixture {
> -		char buf[64];
> -		FILE *status;
> +		char buf[128];
>  
>  		data.drm_fd = drm_open_any_master();
>  		kmstest_set_vt_graphics_mode();
> @@ -554,11 +548,7 @@ igt_main
>  
>  		igt_require_pipe_crc();
>  
> -		status = igt_debugfs_fopen("i915_fbc_status", "r");
> -		igt_require_f(status, "No i915_fbc_status found\n");
> -		igt_assert_lt(0, fread(buf, 1, sizeof(buf), status));
> -		fclose(status);
> -		buf[sizeof(buf) - 1] = '\0';
> +		igt_debugfs_read("i915_fbc_status", buf, sizeof(buf));
>  		igt_require_f(!strstr(buf, "unsupported on this chipset"),
>  			      "FBC not supported\n");
>  
> diff --git a/tests/kms_fbcon_fbt.c b/tests/kms_fbcon_fbt.c
> index f075014..c201fde 100644
> --- a/tests/kms_fbcon_fbt.c
> +++ b/tests/kms_fbcon_fbt.c
> @@ -86,28 +86,11 @@ static void teardown_drm(struct drm_info *drm)
>  	igt_assert(close(drm->fd) == 0);
>  }
>  
> -static void debugfs_read(const char *filename, char *buf, int buf_size)
> -{
> -	FILE *file;
> -	size_t n_read;
> -
> -	file = igt_debugfs_fopen(filename, "r");
> -	igt_assert(file);
> -
> -	n_read = fread(buf, 1, buf_size - 1, file);
> -	igt_assert(n_read > 0);
> -	igt_assert(feof(file));
> -
> -	buf[n_read] = '\0';
> -
> -	igt_assert(fclose(file) == 0);
> -}
> -
>  static bool fbc_supported_on_chipset(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  	return !strstr(buf, "FBC unsupported on this chipset\n");
>  }
>  
> @@ -120,7 +103,7 @@ static bool fbc_is_enabled(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "FBC enabled\n");
>  }
>  
> @@ -172,7 +155,7 @@ static bool psr_supported_on_chipset(void)
>  {
>  	char buf[256];
>  
> -	debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "Sink_Support: yes\n");
>  }
>  
> @@ -185,7 +168,7 @@ static bool psr_is_enabled(void)
>  {
>  	char buf[256];
>  
> -	debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "\nActive: yes\n");
>  }
>  
> diff --git a/tests/kms_frontbuffer_tracking.c b/tests/kms_frontbuffer_tracking.c
> index e9be045..e162e91 100644
> --- a/tests/kms_frontbuffer_tracking.c
> +++ b/tests/kms_frontbuffer_tracking.c
> @@ -556,28 +556,11 @@ static bool set_mode_for_params(struct modeset_params *params)
>  	return (rc == 0);
>  }
>  
> -static void debugfs_read(const char *filename, char *buf, int buf_size)
> -{
> -	FILE *file;
> -	size_t n_read;
> -
> -	file = igt_debugfs_fopen(filename, "r");
> -	igt_assert(file);
> -
> -	n_read = fread(buf, 1, buf_size - 1, file);
> -	igt_assert(n_read > 0);
> -	igt_assert(feof(file));
> -
> -	buf[n_read] = '\0';
> -
> -	igt_assert(fclose(file) == 0);
> -}
> -
>  static bool fbc_is_enabled(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "FBC enabled\n");
>  }
>  
> @@ -585,7 +568,7 @@ static bool psr_is_enabled(void)
>  {
>  	char buf[256];
>  
> -	debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
>  	return (strstr(buf, "\nActive: yes\n"));
>  }
>  
> @@ -596,7 +579,7 @@ static struct timespec fbc_get_last_action(void)
>  	char *action;
>  	ssize_t n_read;
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  
>  	action = strstr(buf, "\nLast action:");
>  	igt_assert(action);
> @@ -645,7 +628,7 @@ static void fbc_setup_last_action(void)
>  	char buf[128];
>  	char *action;
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  
>  	action = strstr(buf, "\nLast action:");
>  	if (!action) {
> @@ -664,7 +647,7 @@ static bool fbc_is_compressing(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "\nCompressing: yes\n") != NULL;
>  }
>  
> @@ -677,7 +660,7 @@ static void fbc_setup_compressing(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  
>  	if (strstr(buf, "\nCompressing:"))
>  		fbc.supports_compressing = true;
> @@ -1187,7 +1170,7 @@ static bool fbc_supported_on_chipset(void)
>  {
>  	char buf[128];
>  
> -	debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_fbc_status", buf, ARRAY_SIZE(buf));
>  	return !strstr(buf, "FBC unsupported on this chipset\n");
>  }
>  
> @@ -1211,7 +1194,7 @@ static bool psr_sink_has_support(void)
>  {
>  	char buf[256];
>  
> -	debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
> +	igt_debugfs_read("i915_edp_psr_status", buf, ARRAY_SIZE(buf));
>  	return strstr(buf, "Sink_Support: yes\n");
>  }
>  
> -- 
> 2.1.4
> 
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> Intel-gfx at lists.freedesktop.org
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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