Commit 04a3f959 authored Aug 10, 2007 by Helge Deller Committed by Linus Torvalds Aug 11, 2007

stifb: detect cards in double buffer mode more reliably

Visualize-EG, Graffiti and A4450A graphics cards on PARISC can
be configured in double-buffer and standard mode, but the stifb
driver supports standard mode only.
This patch detects double-buffered cards more reliable.

It is a real bugfix for a very nasty problem for all parisc users which have
wrongly configured their graphic card.  The problem: The stifb graphics driver
will not detect that the card is wrongly configured and then nevertheless just
enables the graphics mode, which it shouldn't.  In the end, the user will see
no further updates / boot messages on the screen.

We had documented this problem already on our FAQ
(http://parisc-linux.org/faq/index.html#viseg

 "Why do I get corrupted graphics
with my Vis-EG/Graffiti/A4450A card?") but people still run into this problem.
 So having this fix in as early as possible can help us.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Cc: <stable@kernel.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6a648fa7

drivers/video/stifb.c

+12 −7

Original line number	Diff line number	Diff line
		@@ -1100,13 +1100,18 @@ stifb_init_fb(struct sti_struct *sti, int bpp_pref)
		/* only supported cards are allowed */
		switch (fb->id) {
		case CRT_ID_VISUALIZE_EG:
		/* look for a double buffering device like e.g. the
		"INTERNAL_EG_DX1024" in the RDI precisionbook laptop
		which won't work. The same device in non-double
		buffering mode returns "INTERNAL_EG_X1024". */
		if (strstr(sti->outptr.dev_name, "EG_DX")) {
		printk(KERN_WARNING
		"stifb: ignoring '%s'. Disable double buffering in IPL menu.\n",
		/* Visualize cards can run either in "double buffer" or
		"standard" mode. Depending on the mode, the card reports
		a different device name, e.g. "INTERNAL_EG_DX1024" in double
		buffer mode and "INTERNAL_EG_X1024" in standard mode.
		Since this driver only supports standard mode, we check
		if the device name contains the string "DX" and tell the
		user how to reconfigure the card. */
		if (strstr(sti->outptr.dev_name, "DX")) {
		printk(KERN_WARNING "WARNING: stifb framebuffer driver does not "
		"support '%s' in double-buffer mode.\n"
		KERN_WARNING "WARNING: Please disable the double-buffer mode "
		"in IPL menu (the PARISC-BIOS).\n",
		sti->outptr.dev_name);
		goto out_err0;
		}

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