From 88ece11d6c45c6f4b94f7fb2da64a46e879d7c27 Mon Sep 17 00:00:00 2001
From: Adam Jackson <ajax@redhat.com>
Date: Mon, 3 Dec 2007 15:47:39 -0500
Subject: [PATCH] Start E-EDID support in the DDC module.

Since there's no way to safely know how many blocks xf86DoEDID_DDC2 would
return, add a new xf86DoEEDID entrypoint to do that, and implement the
one in terms of the other.
---
 hw/xfree86/ddc/xf86DDC.c | 110 ++++++++++++++++++++++-----------------
 hw/xfree86/ddc/xf86DDC.h |   2 +
 2 files changed, 65 insertions(+), 47 deletions(-)

diff --git a/hw/xfree86/ddc/xf86DDC.c b/hw/xfree86/ddc/xf86DDC.c
index 28e2ead28..98f60061e 100644
--- a/hw/xfree86/ddc/xf86DDC.c
+++ b/hw/xfree86/ddc/xf86DDC.c
@@ -2,6 +2,14 @@
  * 
  * Copyright 1998,1999 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
  */
+
+/*
+ * Note that DDC1 does not define any method for returning blocks beyond
+ * the first.  DDC2 does, but the original implementation would only ever
+ * read the first block.  If you want to read and parse all blocks, use
+ * xf86DoEEDID().
+ */
+
 #ifdef HAVE_XORG_CONFIG_H
 #include <xorg-config.h>
 #endif
@@ -31,11 +39,6 @@ static unsigned int *FetchEDID_DDC1(
     register unsigned int (*)(ScrnInfoPtr)
 );
 
-static unsigned char* EDID1Read_DDC2(
-    int scrnIndex, 
-    I2CBusPtr pBus
-);
-
 static unsigned char * DDCRead_DDC2(
     int scrnIndex,
     I2CBusPtr pBus, 
@@ -107,6 +110,59 @@ xf86DoEDID_DDC1(
 	return tmp;
 }
 
+/**
+ * Attempts to probe the monitor for EDID information, if NoDDC and NoDDC2 are
+ * unset.  EDID information blocks are interpreted and the results returned in
+ * an xf86MonPtr.  Unlike xf86DoEDID_DDC[12](), this function will return
+ * the complete EDID data, including all extension blocks.
+ *
+ * This function does not affect the list of modes used by drivers -- it is up
+ * to the driver to decide policy on what to do with EDID information.
+ *
+ * @return pointer to a new xf86MonPtr containing the EDID information.
+ * @return NULL if no monitor attached or failure to interpret the EDID.
+ *
+ * nblocks is an in/out parameter.  If non-zero, it defines the number of
+ * blocks to read from the monitor; zero (or NULL pointer) means read all.
+ * If non-NULL, on return it will be filled in with the number of blocks
+ * read.
+ */
+xf86MonPtr
+xf86DoEEDID(int scrnIndex, I2CBusPtr pBus, int *nblocks)
+{
+    ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
+    unsigned char *EDID_block = NULL;
+    xf86MonPtr tmp = NULL;
+    /* Default DDC and DDC2 to enabled. */
+    Bool noddc = FALSE, noddc2 = FALSE;
+    OptionInfoPtr options;
+
+    options = xnfalloc(sizeof(DDCOptions));
+    memcpy(options, DDCOptions, sizeof(DDCOptions));
+    xf86ProcessOptions(pScrn->scrnIndex, pScrn->options, options);
+
+    xf86GetOptValBool(options, DDCOPT_NODDC, &noddc);
+    xf86GetOptValBool(options, DDCOPT_NODDC2, &noddc2);
+    xfree(options);
+    
+    if (noddc || noddc2)
+	return NULL;
+
+    EDID_block = DDCRead_DDC2(scrnIndex, pBus, 0, EDID1_LEN);
+
+    if (EDID_block)
+	tmp = xf86InterpretEDID(scrnIndex, EDID_block);
+
+    if (nblocks) {
+	if (tmp)
+	    *nblocks = tmp->no_sections;
+	else
+	    *nblocks = 0;
+    }
+
+    return tmp;
+}
+
 /**
  * Attempts to probe the monitor for EDID information, if NoDDC and NoDDC2 are
  * unset.  EDID information blocks are interpreted and the results returned in
@@ -121,42 +177,8 @@ xf86DoEDID_DDC1(
 xf86MonPtr
 xf86DoEDID_DDC2(int scrnIndex, I2CBusPtr pBus)
 {
-    ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
-    unsigned char *EDID_block = NULL;
-    xf86MonPtr tmp = NULL;
-    /* Default DDC and DDC2 to enabled. */
-    Bool noddc = FALSE, noddc2 = FALSE;
-    OptionInfoPtr options;
-
-    options = xnfalloc(sizeof(DDCOptions));
-    (void)memcpy(options, DDCOptions, sizeof(DDCOptions));
-    xf86ProcessOptions(pScrn->scrnIndex, pScrn->options, options);
-
-    xf86GetOptValBool(options, DDCOPT_NODDC, &noddc);
-    xf86GetOptValBool(options, DDCOPT_NODDC2, &noddc2);
-    xfree(options);
-    
-    if (noddc || noddc2)
-	return NULL;
-
-    EDID_block = EDID1Read_DDC2(scrnIndex,pBus);
-
-    if (EDID_block){
-	tmp = xf86InterpretEDID(scrnIndex,EDID_block);
-    } else {
-#ifdef DEBUG
-	ErrorF("No EDID block returned\n");
-#endif
-	return NULL;
-    }
-#ifdef DEBUG
-    if (!tmp)
-	ErrorF("Cannot interpret EDID block\n");
-    else
-        ErrorF("Sections to follow: %i\n",tmp->no_sections);
-#endif
-    
-    return tmp;
+    int nblocks = 1;
+    return xf86DoEEDID(scrnIndex, pBus, &nblocks);
 }
 
 /* 
@@ -226,12 +248,6 @@ FetchEDID_DDC1(register ScrnInfoPtr pScrn,
     return (ptr);
 }
 
-static unsigned char*
-EDID1Read_DDC2(int scrnIndex, I2CBusPtr pBus)
-{
-    return  DDCRead_DDC2(scrnIndex, pBus, 0, EDID1_LEN);
-}
-
 static unsigned char *
 DDCRead_DDC2(int scrnIndex, I2CBusPtr pBus, int start, int len)
 {
diff --git a/hw/xfree86/ddc/xf86DDC.h b/hw/xfree86/ddc/xf86DDC.h
index 3b072dda7..6e5bf6f7a 100644
--- a/hw/xfree86/ddc/xf86DDC.h
+++ b/hw/xfree86/ddc/xf86DDC.h
@@ -35,6 +35,8 @@ extern xf86MonPtr xf86DoEDID_DDC2(
    I2CBusPtr pBus
 );
 
+extern xf86MonPtr xf86DoEEDID(int scrnIndex, I2CBusPtr pBus, int *nblocks);
+
 extern xf86MonPtr xf86PrintEDID(
     xf86MonPtr monPtr
 );