PInS data on later cards (G200 and later) contains information about the

    physical bus used for the card. This allows accurate detection of PCI
    cards that use a PCI-to-PCI bridge with an AGP chip.
Correctly disable DRI on PCI cards used with pre-3.2 DRM. Previously the
    test was performed based on PCI ID (see above for why this is wrong)
    and was done *before* the DRM version was known.
Bug #3759: <https://bugs.freedesktop.org/show_bug.cgi?id=3759> Correctly
    determine the PLL reference frequency from the PInS data. Previously
    the wrong bit was tested. Blame the dumb programmer that used
    cut-and-paste (that would be me).

4 files changed, 92 insertions, 18 deletions

diff --git a/src/mga.h b/src/mga.h
index 46c4dbe..32ea21b 100644
--- a/src/mga.h
+++ b/src/mga.h
@@ -305,6 +305,26 @@ struct mga_VCO {
 };
 
 /**
+ * Host interface types that can be set by the card's BIOS.
+ */
+typedef enum {
+    MGA_HOST_UNKNOWN0 = 0,  /**< Meaning unknown. */
+    MGA_HOST_UNKNOWN1 = 1,  /**< Meaning unknown. */
+    MGA_HOST_UNKNOWN2 = 2,  /**< Meaning unknown. */
+    MGA_HOST_HYBRID = 3,    /**< AGP 4x for data xfers only. */
+
+    /**
+     * PCI interface.  Either native or via a universal PCI-to-PCI bridge
+     * chip.  The PCI G450 and PCI G550 cards are examples.
+     */
+    MGA_HOST_PCI = 4,
+
+    MGA_HOST_AGP_1x = 5,    /**< AGP 1x capable. */
+    MGA_HOST_AGP_2x = 6,    /**< AGP 2x capable. */
+    MGA_HOST_AGP_4x = 7     /**< AGP 4x capable. */
+} mga_host_t;
+
+/**
  * Card information derrived from BIOS PInS data.
  */
 struct mga_bios_values {
@@ -339,6 +359,11 @@ struct mga_bios_values {
      * by a capability bit stored in the PInS data.
      */
     Bool fast_bitblt;
+
+    /**
+     * Type of physical interface used for the card.
+     */
+    mga_host_t host_interface;
 };
 
 
diff --git a/src/mga_bios.c b/src/mga_bios.c
index 05e5a4f..8afd1ec 100644
--- a/src/mga_bios.c
+++ b/src/mga_bios.c
@@ -58,6 +58,9 @@
 
 #include "mga.h"
 
+#if defined(DEBUG)
+#define BIOS_DEBUG
+#endif
 
 /**
  * Read a little-endian, unaligned data value and return as 16-bit.
@@ -125,6 +128,9 @@ static void mga_initialize_bios_values( MGAPtr pMga,
 
 	bios->pll_ref_freq = 14318;
 	bios->mem_clock = 50000;
+
+	bios->host_interface = (pMga->Chipset == PCI_CHIP_MGA2164_AGP) 
+	  ? MGA_HOST_AGP_1x : MGA_HOST_PCI;
 	break;
 
     case PCI_CHIP_MGA1064:
@@ -138,6 +144,7 @@ static void mga_initialize_bios_values( MGAPtr pMga,
 
 	bios->pll_ref_freq = 14318;
 	bios->mem_clock = 50000;
+	bios->host_interface = MGA_HOST_PCI;
 	break;
 
     case PCI_CHIP_MGAG100_PCI:
@@ -151,6 +158,16 @@ static void mga_initialize_bios_values( MGAPtr pMga,
 
 	bios->pll_ref_freq = 27050;
 	bios->mem_clock = 50000;
+
+	if ( pMga->Chipset == PCI_CHIP_MGAG100 ) {
+	    bios->host_interface = MGA_HOST_AGP_1x;
+	}
+	else if ( pMga->Chipset == PCI_CHIP_MGAG200 ) {
+	    bios->host_interface = MGA_HOST_AGP_2x;
+	}
+	else {
+	    bios->host_interface = MGA_HOST_PCI;
+	}
 	break;
 
     case PCI_CHIP_MGAG400:
@@ -161,6 +178,7 @@ static void mga_initialize_bios_values( MGAPtr pMga,
 
 	bios->pll_ref_freq = 27050;
 	bios->mem_clock = 200000;
+	bios->host_interface = MGA_HOST_AGP_4x;
 	break;
 
     case PCI_CHIP_MGAG550:
@@ -173,6 +191,7 @@ static void mga_initialize_bios_values( MGAPtr pMga,
 
 	bios->pll_ref_freq = 27050;
 	bios->mem_clock = 284000;
+	bios->host_interface = MGA_HOST_AGP_4x;
 	break;
     }
 }
@@ -263,7 +282,7 @@ static void mga_parse_bios_ver_3( struct mga_bios_values * bios,
 	bios->system.max_freq = maxdac;
     }
 
-    if ( (bios_data[52] & 0x01) != 0 ) {
+    if ( (bios_data[52] & 0x20) != 0 ) {
 	bios->pll_ref_freq = 14318;
     }
 }
@@ -294,6 +313,8 @@ static void mga_parse_bios_ver_4( struct mga_bios_values * bios,
 	bios->pll_ref_freq = 14318;
     }
 
+    bios->host_interface = (bios_data[95] >> 3) & 0x07;
+
     if ( bios_data[65] != 0xff ) {
 	const unsigned system_pll = bios_data[65] * 4 * 1000;
 	bios->mem_clock = system_pll;
@@ -365,6 +386,8 @@ static void mga_parse_bios_ver_5( struct mga_bios_values * bios,
     if ( (bios_data[110] & 0x01) != 0 ) {
 	bios->pll_ref_freq = 14318;
     }
+
+    bios->host_interface = (bios_data[113] >> 3) & 0x07;
 }
 
 
@@ -383,6 +406,18 @@ Bool mga_read_and_process_bios( ScrnInfoPtr pScrn )
     unsigned version;
     unsigned pins_len;
     const CARD8 * pins_data;
+#ifdef BIOS_DEBUG
+    static const char * const host_interface_strings[8] = {
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Hybrid (AGP 4x on data transfers only)",
+	"PCI",
+	"AGP 1x",
+	"AGP 2x",
+	"AGP 4x"
+    };
+#endif
 
 
     /* Initialize the stored BIOS data to some reasonable values for the
@@ -501,7 +536,7 @@ Bool mga_read_and_process_bios( ScrnInfoPtr pScrn )
     case 5:  mga_parse_bios_ver_5( & pMga->bios, pins_data ); break;
     }
     
-#ifdef DEBUG
+#ifdef BIOS_DEBUG
     xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 	       "system VCO = [%u, %u]\n",
 	       pMga->bios.system.min_freq, pMga->bios.system.max_freq);
@@ -519,6 +554,10 @@ Bool mga_read_and_process_bios( ScrnInfoPtr pScrn )
     xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 	       "%s fast bitblt\n",
 	       (pMga->bios.fast_bitblt) ? "Has" : "Does not have");
+    xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+	       "Host interface: %s (%u)\n",
+	       host_interface_strings[ pMga->bios.host_interface ],
+	       pMga->bios.host_interface);
 #endif
 
     return TRUE;
diff --git a/src/mga_dacG.c b/src/mga_dacG.c
index 3385636..728dd89 100644
--- a/src/mga_dacG.c
+++ b/src/mga_dacG.c
@@ -170,8 +170,9 @@ MGAGCalcClock ( ScrnInfoPtr pScrn, long f_out,
 		*s = 3;	
 
 #ifdef DEBUG
-	ErrorF( "f_out_requ =%ld f_pll_real=%.1f f_vco=%.1f n=0x%x m=0x%x p=0x%x s=0x%x\n",
-		f_out, f_pll, f_vco, *best_n, *best_m, *p, *s );
+	xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+		   "f_out_requ =%ld f_pll_real=%.1f f_vco=%.1f n=0x%x m=0x%x p=0x%x s=0x%x\n",
+		   f_out, (f_vco / (*p + 1)), f_vco, *best_n, *best_m, *p, *s );
 #endif
 }
 
diff --git a/src/mga_dri.c b/src/mga_dri.c
index 25b8a8c..bcaf03e 100644
--- a/src/mga_dri.c
+++ b/src/mga_dri.c
@@ -592,6 +592,10 @@ static unsigned int mylog2( unsigned int n )
  * \todo
  * The sizes used for the primary DMA buffer and the bin size and count for
  * the secondary DMA buffers should be configurable from the xorg.conf.
+ * 
+ * \todo
+ * This routine should use \c mga_bios_values::host_interface to limit the
+ * AGP mode.  It the card is PCI, \c MGARec::agpSize should be forced to 0.
  */
 static Bool MGADRIBootstrapDMA(ScreenPtr pScreen)
 {
@@ -977,22 +981,10 @@ Bool MGADRIScreenInit( ScreenPtr pScreen )
    case PCI_CHIP_MGAG550:
    case PCI_CHIP_MGAG400:
    case PCI_CHIP_MGAG200:
-       break;
    case PCI_CHIP_MGAG200_PCI:
-       /* PCI cards are supported if the DRM version is at least 3.2 and the
-	* user has not explicitly disabled the new DMA init path (i.e., to
-	* support old version of the client-side driver that don't use the
-	* new features of the 3.2 DRM).
-	*/
-       if ( (pMGADRIServer->drm_version_minor >= 2) && !pMga->useOldDmaInit ) {
-	   break;
-       }
-       /*FALLTHROUGH*/
+       break;
    default:
-       xf86DrvMsg(pScrn->scrnIndex, X_ERROR, 
-		  "[drm] Direct rendering only supported with G200/G400/G550 AGP.  PCI cards\n"
-		  "[drm] (G450 and G200) are only supported with DRM version 3.2 or higher and\n"
-		  "[drm] a recent client-side driver.\n");
+       xf86DrvMsg(pScrn->scrnIndex, X_ERROR, "[drm] Direct rendering only supported with G200/G400/G450/G550.\n");
        return FALSE;
    }
 
@@ -1218,6 +1210,23 @@ Bool MGADRIScreenInit( ScreenPtr pScreen )
       }
    }
 
+   if ( (pMga->bios.host_interface == MGA_HOST_PCI) &&
+	((pMGADRIServer->drm_version_minor < 2) || pMga->useOldDmaInit) ) {
+       /* PCI cards are supported if the DRM version is at least 3.2 and the
+	* user has not explicitly disabled the new DMA init path (i.e., to
+	* support old version of the client-side driver that don't use the
+	* new features of the 3.2 DRM).
+	*/
+       xf86DrvMsg(pScrn->scrnIndex, X_ERROR, 
+		  "[drm] Direct rendering on PCI cards requires DRM version 3.2 or higher\n"
+       xf86DrvMsg(pScrn->scrnIndex, X_ERROR, 
+		  "[drm] and a recent client-side driver.  Also make sure that 'OldDmaInit'\n"
+       xf86DrvMsg(pScrn->scrnIndex, X_ERROR, 
+		  "[drm] is not selected in xorg.conf.'\n");
+       return FALSE;
+   }
+
+
    if ( !MGADRIBootstrapDMA( pScreen ) ) {
       DRICloseScreen( pScreen );
       return FALSE;