On Mon, 18 Oct 2021, luo penghao cgel.zte@gmail.com wrote:
Variable is not used in the loop, and its assignment is redundant too. So it should be deleted.
The clang_analyzer complains as follows:
drivers/gpu/drm/i915/display/intel_fb.c:1018:3 warning:
Value stored to 'cpp' is never read.
Reported-by: Zeal Robot zealci@zte.com.cn Signed-off-by: luo penghao luo.penghao@zte.com.cn
drivers/gpu/drm/i915/display/intel_fb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c index fa1f375..b9b6a7a 100644 --- a/drivers/gpu/drm/i915/display/intel_fb.c +++ b/drivers/gpu/drm/i915/display/intel_fb.c @@ -998,7 +998,7 @@ int intel_fill_fb_info(struct drm_i915_private *i915, struct intel_framebuffer * for (i = 0; i < num_planes; i++) { struct fb_plane_view_dims view_dims; unsigned int width, height;
unsigned int cpp, size;
unsigned int size;@@ -1015,7 +1015,7 @@ int intel_fill_fb_info(struct drm_i915_private *i915, struct intel_framebuffer * return -EINVAL; }
cpp = fb->base.format->cpp[i];
fb->base.format->cpp[i];
Thanks for the report. However, this "fix" isn't any better than having the unused variable. It's obviously wrong.
It would be useful to dig into the history of the function, and figure out when and why the variable became unused, and whether that caused an actual bug or whether this was just leftovers from some refactoring.
So that's what I did. Some git blame and git log -p revealed commit d3c5e10b6059 ("drm/i915/intel_fb: Factor out convert_plane_offset_to_xy()") that moved the check that used the cpp variable to a separate function, and the local variable and the line above became unused and useless.
That's the actually helpful part. It's easy to see and verify that the right fix is to just remove the line completely.
BR, Jani.
intel_fb_plane_dims(fb, i, &width, &height); ret = convert_plane_offset_to_xy(fb, i, width, &x, &y);