[PATCH] vgacon: Return the upper half of 512 character fonts

[PATCH] vgacon: Return the upper half of 512 character fonts

[Stefan Bader]

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Not sure who would be considered maintainer for vgacon, so spreading slightly. 
There is a bug in returning the font data for 512 character fonts which seems 
to have evaded all detection. Unlikely to be important enough for stable as it 
won't cause any mayhem.

Regards,
Stefan



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>From e7aa277f2e8d76c4d93991b345a80ef80f461f89 Mon Sep 17 00:00:00 2001
From: Stefan Bader <stefan.bader@canonical.com>
Date: Fri, 17 Apr 2009 23:21:05 +0200
Subject: [PATCH] vgacon: Return the upper half of 512 character fonts

Bug: #355057

Uwe Geuder noted that he gets random bitmaps on a text console if he tried
to type extended characters (like the e acute). For him everything above
unicode 0xa0 was corrupted.

After some digging there seems to be a little culprit in vgacon since the
beginning of ages (well git). The function vgacon_font_get will store the
number of characters correctly in font->charcount but then calls to
vgacon_do_font_op(..., 0, 0). Which means only the lower 256 characters are
actually stored to the fontdata. The rest is left untouched. So the next time
that saved data is used, the garbled font appears. This happens on every
switch between text consoles.

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Tested-by: Uwe Geuder <ubuntuLp-ugeuder@sneakemail.com>
---
 drivers/video/console/vgacon.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index d012edd..38e86b8 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1282,7 +1282,7 @@ static int vgacon_font_get(struct vc_data *c, struct console_font *font)
 	font->charcount = vga_512_chars ? 512 : 256;
 	if (!font->data)
 		return 0;
-	return vgacon_do_font_op(&state, font->data, 0, 0);
+	return vgacon_do_font_op(&state, font->data, 0, vga_512_chars);
 }
 
 #else
-- 
1.5.4.3

Re: [PATCH] vgacon: Return the upper half of 512 character fonts

[Andrew Morton]

On Tue, 21 Apr 2009 16:43:26 +0200
Stefan Bader <stefan.bader@canonical.com> wrote:

> From: Stefan Bader <stefan.bader@canonical.com>
> Date: Fri, 17 Apr 2009 23:21:05 +0200
> Subject: [PATCH] vgacon: Return the upper half of 512 character fonts
> 
> Bug: #355057

I think it's OK (and often good) to include the bug references in the
changelog.  But nobody will have any clue which bug tracking system
this refers to!

A full URL would be appropriate.

<googles for a while>

The form I use is

	Addresses https://bugs.launchpad.net/ubuntu/+source/linux/+bug/355057

Re: [PATCH] vgacon: Return the upper half of 512 character fonts

[Stefan Bader]

Andrew Morton wrote:
> On Tue, 21 Apr 2009 16:43:26 +0200
> Stefan Bader <stefan.bader@canonical.com> wrote:
> 
>> From: Stefan Bader <stefan.bader@canonical.com>
>> Date: Fri, 17 Apr 2009 23:21:05 +0200
>> Subject: [PATCH] vgacon: Return the upper half of 512 character fonts
>>
>> Bug: #355057
> 
> I think it's OK (and often good) to include the bug references in the
> changelog.  But nobody will have any clue which bug tracking system
> this refers to!
> 
> A full URL would be appropriate.
> 
> <googles for a while>
> 
> The form I use is
> 
> 	Addresses https://bugs.launchpad.net/ubuntu/+source/linux/+bug/355057
> 
True, the current form is used here to generate changelog and either should not 
go outside or, even better, I should make it a default to add another tag with 
the complete link which then helps all.

Stefan

-- 

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