xfree86: Make driver matching consistent

Most of the driver enumeration functions take an array and a maximum
number of entries that they are allowed to fill in. Upon success, they
return the number of entries filled in. This allows them to be easily
used to consecutively.

One exception is the xf86MatchDriverFromFiles() function, which doesn't
return a value, so callers have to manually search the array for the
first empty entry.

This commit modifies the xf86MatchDriverFromFiles() to behave the same
way as others, which makes it easier to deal with.

Reviewed-by: Aaron Plattner <aplattner@nvidia.com>
Tested-By: Aaron Plattner <aplattner@nvidia.com>
Tested-by: Rob Clark <robdclark@gmail.com>  (on arm / platform device)
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

hw/xfree86/common/xf86AutoConfig.c

@@ -265,7 +265,7 @@ listPossibleVideoDrivers(char *matches[], int nmatches)
 #endif
 #ifdef XSERVER_LIBPCIACCESS
     if (i < (nmatches - 1))
-        i = xf86PciMatchDriver(matches, nmatches);
+        i += xf86PciMatchDriver(&matches[i], nmatches - i);
 #endif
 
 #if defined(__linux__)

hw/xfree86/common/xf86pciBus.c

@@ -1320,8 +1320,9 @@ xchomp(char *line)
  * don't export their PCI ID's properly. If distros don't end up using this
  * feature it can and should be removed because the symbol-based resolution
  * scheme should be the primary one */
-void
+int
-xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_chip)
+xf86MatchDriverFromFiles(uint16_t match_vendor, uint16_t match_chip,
+                         char *matches[], int nmatches)
 {
     DIR *idsdir;
     FILE *fp;
@@ -1331,11 +1332,11 @@ xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_c
     ssize_t read;
     char path_name[256], vendor_str[5], chip_str[5];
     uint16_t vendor, chip;
-    int i, j;
+    int i = 0, j;
 
     idsdir = opendir(PCI_TXT_IDS_PATH);
     if (!idsdir)
-        return;
+        return 0;
 
     xf86Msg(X_INFO,
             "Scanning %s directory for additional PCI ID's supported by the drivers\n",
@@ -1386,10 +1387,6 @@ xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_c
                         }
                     }
                     if (vendor == match_vendor && chip == match_chip) {
-                        i = 0;
-                        while (matches[i]) {
-                            i++;
-                        }
                         matches[i] =
                             (char *) malloc(sizeof(char) *
                                             strlen(direntry->d_name) - 3);
@@ -1412,6 +1409,7 @@ xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_c
                         }
                         xf86Msg(X_INFO, "Matched %s from file name %s\n",
                                 matches[i], direntry->d_name);
+                        i++;
                     }
                 }
                 else {
@@ -1425,6 +1423,7 @@ xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_c
  end:
     free(line);
     closedir(idsdir);
+    return i;
 }
 #endif                          /* __linux__ */
 
@@ -1435,7 +1434,7 @@ xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_c
 int
 xf86PciMatchDriver(char *matches[], int nmatches)
 {
-    int i;
+    int i = 0;
     struct pci_device *info = NULL;
     struct pci_device_iterator *iter;
 
@@ -1450,13 +1449,10 @@ xf86PciMatchDriver(char *matches[], int nmatches)
     pci_iterator_destroy(iter);
 #ifdef __linux__
     if (info)
-        xf86MatchDriverFromFiles(matches, info->vendor_id, info->device_id);
+        i += xf86MatchDriverFromFiles(info->vendor_id, info->device_id,
+                                      matches, nmatches);
 #endif
 
-    for (i = 0; (i < nmatches) && (matches[i]); i++) {
-        /* find end of matches list */
-    }
-
     if ((info != NULL) && (i < nmatches)) {
         i += xf86VideoPtrToDriverList(info, &(matches[i]), nmatches - i);
     }

hw/xfree86/common/xf86pciBus.h

@@ -47,8 +47,9 @@ void xf86PciConfigureNewDev(void *busData, struct pci_device *pVideo,
                                  ((x)->func == (y)->func) &&            \
                                  ((x)->dev == (y)->dev))
 
-void
+int
-xf86MatchDriverFromFiles(char **matches, uint16_t match_vendor, uint16_t match_chip);
+xf86MatchDriverFromFiles(uint16_t match_vendor, uint16_t match_chip,
+                         char *matches[], int nmatches);
 int
 xf86VideoPtrToDriverList(struct pci_device *dev,
                          char *returnList[], int returnListMax);

hw/xfree86/common/xf86platformBus.c

@@ -221,13 +221,10 @@ xf86PlatformMatchDriver(char *matches[], int nmatches)
             info = xf86_platform_devices[i].pdev;
 #ifdef __linux__
             if (info)
-                xf86MatchDriverFromFiles(matches, info->vendor_id, info->device_id);
+                j += xf86MatchDriverFromFiles(info->vendor_id, info->device_id,
+                                              &matches[j], nmatches - j);
 #endif
 
-            for (j = 0; (j < nmatches) && (matches[j]); j++) {
-                /* find end of matches list */
-            }
-
             if ((info != NULL) && (j < nmatches)) {
                 j += xf86VideoPtrToDriverList(info, &(matches[j]), nmatches - j);
             }