svn commit: r356571 - stable/12/stand/i386/libi386

[Toomas Soome]

Author: tsoome
Date: Thu Jan  9 21:37:50 2020
New Revision: 356571
URL: https://svnweb.freebsd.org/changeset/base/356571

Log:
  MFC r356570:
  loader: bioscd probe can get sector size 0
  
  With buggy BIOS, it may happen we get sector size reported 0 for cd, and then
  the default 512 is used, which is quite wrong.
  
  PR:		238749

Modified:
  stable/12/stand/i386/libi386/biosdisk.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/stand/i386/libi386/biosdisk.c
==============================================================================
--- stable/12/stand/i386/libi386/biosdisk.c	Thu Jan  9 21:21:08 2020	(r356570)
+++ stable/12/stand/i386/libi386/biosdisk.c	Thu Jan  9 21:37:50 2020	(r356571)
@@ -380,7 +380,8 @@ bc_add(int biosdev)
 		return (-1);
 
 	bd->bd_flags = BD_CDROM;
-        bd->bd_unit = biosdev;
+	bd->bd_unit = biosdev;
+	bd->bd_sectorsize = 2048;
 
 	/*
 	 * Ignore result from bd_int13probe(), we will use local
@@ -548,7 +549,8 @@ bd_int13probe(bdinfo_t *bd)
 		bd->bd_flags |= BD_MODEEDD3;
 
 	/* Default sector size */
-	bd->bd_sectorsize = BIOSDISK_SECSIZE;
+	if (bd->bd_sectorsize == 0)
+		bd->bd_sectorsize = BIOSDISK_SECSIZE;
 
 	/*
 	 * Test if the floppy device is present, so we can avoid receiving