Thread (9 messages) 9 messages, 4 authors, 2007-02-28

Re: [PATCH] fbdev driver for S3 Trio/Virge, updated

From: "Antonino A. Daplas" <adaplas@gmail.com>
Date: 2007-02-28 21:33:27
Also in: lkml

On Wed, 2007-02-28 at 16:53 +0000, James Simmons wrote:
quoted
On Thu, 2007-02-22 at 00:53 +0000, James Simmons wrote:
quoted
quoted
quoted
+/* image data is MSB-first, fb structure is MSB-first too */
+static inline u32 expand_color(u32 c)
+{
+	return ((c & 1) | ((c & 2) << 7) | ((c & 4) << 14) | ((c & 8) << 21)) * 0xFF;
+}
+
+/* s3fb_iplan_imageblit silently assumes that almost everything is 8-pixel aligned */
Hmn, same thing with vga16fb... Perhaps we should bring back the
fontwidth flag of 2.2 and 2.4 kernels.
Ug no. It is possible to get 12,6 bit width fonts working with vga 
interleaved planes. I got it paritally working but never got back to it.
Its in my queue of this to do. Now that I finished the display class I 
need to get around to makeing drm/fbdev work together :-)
Of course, not fontwidth exactly, but to allow the driver to specify the
alignment of the blit engine, in this case 8 pixels. I do believe X also
has similar functionality to compensate for the limitation of the
hardware.
Isn't scan_align in pixmap for this? Or do we need more.
No, scan_align is how much to pad each line, and it's up to the engine
to discard the padding.  In this case, the hardware does not allow
padding and must be given data in exact multiples. For example, vesafb
can accept 4x4 fonts padded to 8x4, but vga16fb will not be able to draw
4x4 fonts properly.

Tony
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