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DRM: clean up and document parsing of video= parameter 

The video= parameter of the DRM drivers supports some additional flags that
the normal fb drivers do not have. They also allow to limit these flags to
specific outputs. Both things were previously undocumented.

Also the parsing of the line had some oddities:
-A lot of misplaced options were silently ignored or partly rejected instead
 of stopping the parsing immediately
-The 'R' option is documented to follow the 'M' option if specified. It is not
 documented that 'M' is needed to specify 'R' (also this is the case for normal
 fb drivers). In fact the code is correct for normal fb drivers but wrong for
 DRM ones.
 The old code allowed 'R' only _before_ 'M' (since it parses backwards) and only
 if 'M' is given at all which is not needed for the DRM drivers.
-the margins option ('m') was parsed but later ignored even if the later
 functions support it.
-specifying multiple enable options at the same time did not lead to an error.
-specifying something bogus for horizontal resolution (i.e. other things as
 digits) did not lead to an error but an invalid resolution was used.

If any errors are encountered the position of the faulting string is now
printed to the user and the complete mode is ignored. This gives much
more consistent error behaviour.

I also removed some useless assignments and changed the local flag variables
to be bool.

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Rolf Eike Beer 2011-06-15 11:27:02 +02:00 committed by Dave Airlie
parent ee2762916f
commit 04fee895ef
2 changed files with 78 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
Documentation/fb/modedb.txt
View File

@ -20,7 +20,7 @@ in a video= option, fbmem considers that to be a global video mode option.
Valid mode specifiers (mode_option argument):
<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m]
<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]
<name>[-<bpp>][@<refresh>]
with <xres>, <yres>, <bpp> and <refresh> decimal numbers and <name> a string.
@ -36,6 +36,21 @@ pixels and 1.8% of yres).
Sample usage: 1024x768M@60m - CVT timing with margins
DRM drivers also add options to enable or disable outputs:
'e' will force the display to be enabled, i.e. it will override the detection
if a display is connected. 'D' will force the display to be enabled and use
digital output. This is useful for outputs that have both analog and digital
signals (e.g. HDMI and DVI-I). For other outputs it behaves like 'e'. If 'd'
is specified the output is disabled.
You can additionally specify which output the options matches to.
To force the VGA output to be enabled and drive a specific mode say:
video=VGA-1:1280x1024@60me
Specifying the option multiple times for different ports is possible, e.g.:
video=LVDS-1:d video=HDMI-1:D
***** oOo ***** oOo ***** oOo ***** oOo ***** oOo ***** oOo ***** oOo *****
What is the VESA(TM) Coordinated Video Timings (CVT)?
@ -132,5 +147,5 @@ There may be more modes.
tridentfb - Trident (Cyber)blade chipset frame buffer
vt8623fb - VIA 8623 frame buffer
BTW, only a few drivers use this at the moment. Others are to follow
(feel free to send patches).
BTW, only a few fb drivers use this at the moment. Others are to follow
(feel free to send patches). The DRM drivers also support this.

87
drivers/gpu/drm/drm_modes.c
View File

@ -994,9 +994,10 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
{
const char *name;
unsigned int namelen;
int res_specified = 0, bpp_specified = 0, refresh_specified = 0;
bool res_specified = false, bpp_specified = false, refresh_specified = false;
unsigned int xres = 0, yres = 0, bpp = 32, refresh = 0;
int yres_specified = 0, cvt = 0, rb = 0, interlace = 0, margins = 0;
bool yres_specified = false, cvt = false, rb = false;
bool interlace = false, margins = false, was_digit = false;
int i;
enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
@ -1015,54 +1016,65 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
for (i = namelen-1; i >= 0; i--) {
switch (name[i]) {
case '@':
namelen = i;
if (!refresh_specified && !bpp_specified &&
!yres_specified) {
!yres_specified && !cvt && !rb && was_digit) {
refresh = simple_strtol(&name[i+1], NULL, 10);
refresh_specified = 1;
if (cvt || rb)
cvt = 0;
refresh_specified = true;
was_digit = false;
} else
goto done;
break;
case '-':
namelen = i;
if (!bpp_specified && !yres_specified) {
if (!bpp_specified && !yres_specified && !cvt &&
!rb && was_digit) {
bpp = simple_strtol(&name[i+1], NULL, 10);
bpp_specified = 1;
if (cvt || rb)
cvt = 0;
bpp_specified = true;
was_digit = false;
} else
goto done;
break;
case 'x':
if (!yres_specified) {
if (!yres_specified && was_digit) {
yres = simple_strtol(&name[i+1], NULL, 10);
yres_specified = 1;
yres_specified = true;
was_digit = false;
} else
goto done;
case '0' ... '9':
was_digit = true;
break;
case 'M':
if (!yres_specified)
cvt = 1;
if (yres_specified || cvt || was_digit)
goto done;
cvt = true;
break;
case 'R':
if (cvt)
rb = 1;
if (yres_specified || cvt || rb || was_digit)
goto done;
rb = true;
break;
case 'm':
if (!cvt)
margins = 1;
if (cvt || yres_specified || was_digit)
goto done;
margins = true;
break;
case 'i':
if (!cvt)
interlace = 1;
if (cvt || yres_specified || was_digit)
goto done;
interlace = true;
break;
case 'e':
if (yres_specified || bpp_specified || refresh_specified ||
was_digit || (force != DRM_FORCE_UNSPECIFIED))
goto done;
force = DRM_FORCE_ON;
break;
case 'D':
if (yres_specified || bpp_specified || refresh_specified ||
was_digit || (force != DRM_FORCE_UNSPECIFIED))
goto done;
if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
(connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
force = DRM_FORCE_ON;
@ -1070,17 +1082,37 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
force = DRM_FORCE_ON_DIGITAL;
break;
case 'd':
if (yres_specified || bpp_specified || refresh_specified ||
was_digit || (force != DRM_FORCE_UNSPECIFIED))
goto done;
force = DRM_FORCE_OFF;
break;
default:
goto done;
}
}
if (i < 0 && yres_specified) {
xres = simple_strtol(name, NULL, 10);
res_specified = 1;
char *ch;
xres = simple_strtol(name, &ch, 10);
if ((ch != NULL) && (*ch == 'x'))
res_specified = true;
else
i = ch - name;
} else if (!yres_specified && was_digit) {
/* catch mode that begins with digits but has no 'x' */
i = 0;
}
done:
if (i >= 0) {
printk(KERN_WARNING
"parse error at position %i in video mode '%s'\n",
i, name);
mode->specified = false;
return false;
}
if (res_specified) {
mode->specified = true;
mode->xres = xres;
@ -1096,9 +1128,10 @@ done:
mode->bpp_specified = true;
mode->bpp = bpp;
}
mode->rb = rb ? true : false;
mode->cvt = cvt ? true : false;
mode->interlace = interlace ? true : false;
mode->rb = rb;
mode->cvt = cvt;
mode->interlace = interlace;
mode->margins = margins;
mode->force = force;
return true;