On 02/03/15 12:22, Daniel Stone wrote: >> I don't know why Rob named it like that. "The bpp of the stride"? Shrug. > > It's just the bpp of the pixel format; it's not at all associated with > the stride?
The comment says "this times width is stride", so I thought the naming comes from that train of thought. But I agree, it's just bpp. Here's updated patch: From af0db526ae274d47488ec49577365909eb8f629d Mon Sep 17 00:00:00 2001 From: Tomi Valkeinen <[email protected]> Date: Thu, 25 Sep 2014 19:24:28 +0000 Subject: [PATCH] drm/omap: handle incompatible buffer stride and pixel size omapdrm doesn't check if the pitch of the framebuffer and the color format's bits-per-pixel are compatible. omapdss requires that the stride of a buffer is an integer number of pixels For example, when using modetest with a display that has x resolution of 1280, and using packed 24 RGB mode (3 bytes per pixel), modetest allocates a buffer with a byte stride of 4 * 1280 = 5120. But 5120 / 3 = 1706.666... pixels, which causes wrong colors and a tilt on the screen. Add a check into omapdrm to return an error if the user tries to use such a combination. Note: this is not a HW requirement at least for non-rotation use cases, but a SW driver requirement. In the future we should study if also rotation use cases are fine with any stride size, and if so, change the driver to allow these strides. Signed-off-by: Tomi Valkeinen <[email protected]> --- drivers/gpu/drm/omapdrm/omap_fb.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c index 2975096abdf5..e123b4dee670 100644 --- a/drivers/gpu/drm/omapdrm/omap_fb.c +++ b/drivers/gpu/drm/omapdrm/omap_fb.c @@ -463,6 +463,14 @@ struct drm_framebuffer *omap_framebuffer_init(struct drm_device *dev, goto fail; } + if (pitch % format->planes[i].stride_bpp != 0) { + dev_err(dev->dev, + "buffer pitch (%d bytes) is not a multiple of pixel size (%d bytes)\n", + pitch, format->planes[i].stride_bpp); + ret = -EINVAL; + goto fail; + } + size = pitch * mode_cmd->height / format->planes[i].sub_y; if (size > (omap_gem_mmap_size(bos[i]) - mode_cmd->offsets[i])) { -- 2.3.1
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