Messages in this thread Patch in this message | | | Date | Fri, 24 Sep 2004 15:23:23 +0200 | From | Takashi Iwai <> | Subject | [PATCH] VGA console font problems on 2.6 kernel |
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Hi,
Egbert Eich of Xorg reported the problems of VGA console on 2.6 kernels. I forward his original post and proposed patches here to LKML, since this should be discussed / audited better here.
The patch below can be applied to 2.6.9-rc2.
Any comments, please?
Thanks.
-- Takashi Iwai <tiwai@suse.de> ALSA Developer - www.alsa-project.org
> Subject: [kernel] VGA Text Console Issues > From: Egbert Eich <eich@suse.de> > > I would like to utilize kernel ioctls to save/restore console fonts > in VGA text mode when running X. So far the Xserver takes care of this > however there more and more problems with this: > 1. On some platforms (IA64) we need to POST the BIOS before > we even have a chance to access the hardware ourselves. > This POSTing will usually undo any changes to the graphics > hardware that the kernel may have done. > 2. More and more drivers fully rely on BIOS support however > the BIOS functions which could be used to save/restore > register settings may be broken so the only way of mode > save/restore is getting/setting the BIOS mode ID. > > I've hacked up some code for X however I ran into two problems: > > 1. con_font_get() in linux/drivers/char/vt.c seems to be broken as > the font parameters (height, width, charcount) are never reported > back. Therefore this function seems to be pretty useless. > The fix is simple (please see below). > > 2. fb consoles seem to allow to install fonts per vt so that the user > can have a different font on every console. The text console driver > doesn't support this: the font is downloaded to the video card > and will be used for all systems. Still the vga_con driver stores > the font parameters per console with the effect that setting a > font with different parameters on one console will result in the > wron values when this font information is read back from another > console. > Appearantly this broken feature has been introduced in 2.6 as > in the 2.4 kernel the vga_con font information is stored in one > single global variable. > > The IA64 platform at least still heavily relies on the VGA text console. > To be able to fix some VT switching issues with X on this platform I > need these two issues resolved. > > Egbert.
--- linux/drivers/char/vt.c.orig 2004-09-22 07:12:15.000000000 -0700 +++ linux/drivers/char/vt.c 2004-09-23 07:39:50.206885656 -0700 @@ -3079,6 +3079,10 @@ if (rc) goto out; + op->height = font.height; + op->width = font.width; + op->charcount = font.charcount; + if (op->data && copy_to_user(op->data, font.data, c)) rc = -EFAULT; --- linux/drivers/video/console/vgacon.c 2004-09-23 16:54:02.096337495 +0200 +++ linux/drivers/video/console/vgacon.c 2004-09-23 16:57:32.149761950 +0200 @@ -901,8 +901,10 @@ static int vgacon_adjust_height(struct v for (i = 0; i < MAX_NR_CONSOLES; i++) { struct vc_data *c = vc_cons[i].d; - if (c && c->vc_sw == &vga_con) + if (c && c->vc_sw == &vga_con) { + c->vc_font.height = fontheight; vc_resize(c->vc_num, 0, rows); /* Adjust console size */ + } } return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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