Attachment 15462 Details for Bug 15200 – Patch for the described feature

[patch] Patch for the described feature

xorg_intel_lvdsfixedmode.patch (text/plain), 5.04 KB, created by Mike Isely on 2008-03-25 19:52:42 UTC

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Creator: Mike Isely

Created: 2008-03-25 19:52:42 UTC

Size: 5.04 KB

patch

obsolete

>
>xorg-video-intel: Implement option to ignore external fixed mode settings
>
>From: Mike Isely <isely@pobox.com>
>
>The Intel xorg driver tries mightily to determine the native fixed
>panel mode settings for the LVDS output.  It does this through various
>means, including scanning video BIOS tables, and noticing if the pipe
>in question has already been set up by somebody else (and adopting
>those timings).  This strategy works well for say a laptop where the
>LCD panel is an integral part of the machine.  But for other
>applications where the display is unrelated to the system's BIOS or
>other software, then the BIOS will likely have no clue how to
>configure the LVDS output.  Worse still, the BIOS can simply "get it
>wrong", leaving the pipe misconfigured.  Unfortunately the Intel
>driver can potentially notice this, adopt the same settings, leaving a
>messed up display.
>
>All of this complexity normally happens independently, behind the
>scenes, from the mode timings that might otherwise be specified by the
>user.  This driver has a concept of fixed, i.e. "native" mode, and
>then user-specified mode.  If the corresponding resolutions between
>those concepts don't match, then the driver in theory will arrange for
>scaling to take place while adhering to the actual native mode of the
>panel.  Said another way, if the user says 800x600 but the driver
>mistakenly (see above) thinks the native mode is 640x480, then 640x480
>is the mode set with scaling to an 800x600 frame buffer.  If the
>driver gets the wrong native mode, then the result is a miserable mess
>with no way for the user to override what the driver thinks is right.
>
>This patch provides a means to override the driver.  This implements a
>new driver option, "LVDSFixedMode" which defaults to true (the normal,
>probe-what-I-need behavior).  However when set to false, then all the
>guessing is skipped and the driver will assume no fixed, i.e. "native"
>mode for the display device.  Instead with this option set to false,
>the driver will directly set the timings specified by the user,
>providing an escape hatch for situations where the driver can't
>correctly figure out the right mode.
>
>Under most scenarios of course, this option should not be needed.  But
>in situations where the Intel video BIOS is hopelessly fouled up
>related to the LVDS output, this option provides the escape hatch for
>the user to get a working display in spite of the BIOS situation.
>
>Signed-off-by: Mike Isely <isely@pobox.com>
>
>---
>
>Note: This patch was built against the 2.2.1 driver as patched in
>Debian 2.2.1-1.  However it should apply reasonably well against the
>upstream tree (I hope).
>
> src/i830.h        |    1 +
> src/i830_driver.c |    8 ++++++++
> src/i830_lvds.c   |   10 ++++++++++
> 3 files changed, 19 insertions(+)
>
>Index: src/i830_driver.c
>===================================================================
>--- src/i830_driver.c	(.../debian-2.2.1-1)	(revision 40)
>+++ src/i830_driver.c	(.../patch-lvdsfixedmode)	(revision 40)
>@@ -297,6 +297,7 @@
> #ifdef XF86DRI_MM
>    OPTION_INTELTEXPOOL,
> #endif
>+   OPTION_LVDSFIXEDMODE,
>    OPTION_TRIPLEBUFFER,
>    OPTION_FORCEENABLEPIPEA
> } I830Opts;
>@@ -320,6 +321,7 @@
> #ifdef XF86DRI_MM
>    {OPTION_INTELTEXPOOL,"Legacy3D",     OPTV_BOOLEAN,	{0},	FALSE},
> #endif
>+   {OPTION_LVDSFIXEDMODE, "LVDSFixedMode", OPTV_BOOLEAN,	{0},	FALSE},
>    {OPTION_TRIPLEBUFFER, "TripleBuffer", OPTV_BOOLEAN,	{0},	FALSE},
>    {OPTION_FORCEENABLEPIPEA, "ForceEnablePipeA", OPTV_BOOLEAN,	{0},	FALSE},
>    {-1,			NULL,		OPTV_NONE,	{0},	FALSE}
>@@ -1195,6 +1197,12 @@
>       pI830->debug_modes = FALSE;
>    }
> 
>+   if (xf86ReturnOptValBool(pI830->Options, OPTION_LVDSFIXEDMODE, TRUE)) {
>+      pI830->lvds_fixed_mode = TRUE;
>+   } else {
>+      pI830->lvds_fixed_mode = FALSE;
>+   }
>+
>    if (xf86ReturnOptValBool(pI830->Options, OPTION_FORCEENABLEPIPEA, FALSE))
>        pI830->quirk_flag |= QUIRK_PIPEA_FORCE;
> 
>Index: src/i830.h
>===================================================================
>--- src/i830.h	(.../debian-2.2.1-1)	(revision 40)
>+++ src/i830.h	(.../patch-lvdsfixedmode)	(revision 40)
>@@ -622,6 +622,7 @@
> 
>    /** Enables logging of debug output related to mode switching. */
>    Bool debug_modes;
>+   Bool lvds_fixed_mode;
>    unsigned int quirk_flag;
> } I830Rec;
> 
>Index: src/i830_lvds.c
>===================================================================
>--- src/i830_lvds.c	(.../debian-2.2.1-1)	(revision 40)
>+++ src/i830_lvds.c	(.../patch-lvdsfixedmode)	(revision 40)
>@@ -908,6 +908,14 @@
>      */
>     I830I2CInit(pScrn, &intel_output->pDDCBus, GPIOC, "LVDSDDC_C");
> 
>+    if (!pI830->lvds_fixed_mode) {
>+	xf86DrvMsg(pScrn->scrnIndex, X_INFO,
>+		   "Skipping any attempt to determine panel fixed mode.\n");
>+	goto skip_panel_fixed_mode_setup;
>+    }
>+    xf86DrvMsg(pScrn->scrnIndex, X_INFO,
>+	       "Attempting to determine panel fixed mode.\n");
>+
>     /* Attempt to get the fixed panel mode from DDC.  Assume that the preferred
>      * mode is the right one.
>      */
>@@ -991,6 +999,8 @@
> 	goto disable_exit;
>     }
> 
>+ skip_panel_fixed_mode_setup:
>+
>     /* Blacklist machines with BIOSes that list an LVDS panel without actually
>      * having one.
>      */

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Attachments on bug 15200: 15462 | 15911

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