--- linux-2.4.18.SuSE/drivers/ide/ide-dma.c	Wed Mar 27 10:58:32 2002
+++ linux-2.4.18.SuSE.axp/drivers/ide/ide-dma.c	Fri Apr  5 12:41:34 2002
@@ -326,6 +326,9 @@
 	return pci_map_sg(hwif->pci_dev, sg, nents, hwif->sg_dma_direction);
 }
 
+#if defined(CONFIG_ALPHA_CIA) || defined(CONFIG_ALPHA_GENERIC)
+extern int have_pyxis_pagecross_bug;
+#endif	
 /*
  * ide_build_dmatable() prepares a dma request.
  * Returns 0 if all went okay, returns 1 otherwise.
@@ -377,6 +380,25 @@
 			xcount = bcount & 0xffff;
 			if (is_trm290_chipset)
 				xcount = ((xcount >> 2) - 1) << 16;
+			
+			/* garloff@suse.de, 2001-12-11: Don't cross page boundaries 
+			 * on boards with pyxis dma read page bound cross bug
+			 * when writing (DMA read) */
+#if defined(CONFIG_ALPHA_CIA) || defined(CONFIG_ALPHA_GENERIC)
+			if (have_pyxis_pagecross_bug && func == ide_dma_write
+			    && HWIF(drive)->pci_dev->bus->number == 0) {
+				if (xcount ==0) 
+					xcount = 0x10000;
+				while ((cur_addr & (PAGE_SIZE-1)) + xcount > PAGE_SIZE) {
+					u32 newcnt = PAGE_SIZE - (cur_addr & (PAGE_SIZE-1));
+					if (count++ >= PRD_ENTRIES)
+						goto use_pio_instead;
+					*table++ = cpu_to_le32(newcnt);
+					*table++ = cpu_to_le32(cur_addr += newcnt);
+					xcount -= newcnt;
+				}
+			}
+#endif
 			if (xcount == 0x0000) {
 				/* 
 				 * Most chipsets correctly interpret a length
@@ -389,12 +411,16 @@
 					goto use_pio_instead;
 
 				*table++ = cpu_to_le32(0x8000);
-				*table++ = cpu_to_le32(cur_addr + 0x8000);
+				*table++ = cpu_to_le32(cur_addr += 0x8000);
 				xcount = 0x8000;
 			}
-			*table++ = cpu_to_le32(xcount);
-			cur_addr += bcount;
+			cur_addr += xcount;
 			cur_len -= bcount;
+			// *table++ = cpu_to_le32(xcount | (cur_len? 0: 0x80000000));
+			/* garloff@suse.de, 2001-12-11: We don't mark the last PDR segment
+			 * with EOT bit (31) in length field, but let the drive
+			 * send us an interrupt. */
+			*table++ = cpu_to_le32(xcount);
 		}
 
 		sg++;
--- linux-2.4.18.SuSE/arch/alpha/kernel/core_cia.c	Sun Oct 21 19:30:58 2001
+++ linux-2.4.18.SuSE.axp/arch/alpha/kernel/core_cia.c	Fri Apr  5 12:38:47 2002
@@ -388,6 +388,14 @@
 	*(vip)CIA_IOC_PCI_T1_BASE = virt_to_phys(ppte) >> 2;
 }
 
+/* garloff@suse.de, 2001-12-11:
+ * Flag set, if we suffer PYXIS page crossing corruption on DMA reads.
+ * Note: All PCI devices sitting on primary PCI bus doing busmaster DMA
+ * should check this flag and adjust their SG tables accordingly for reads
+ * from memory (i.e. writes to device). See ide-dma.c code for an example.
+ */
+int have_pyxis_pagecross_bug;
+
 static void __init
 verify_tb_operation(void)
 {
@@ -565,6 +573,8 @@
 	/* Clean up after the tests.  */
 	arena->ptes[4] = 0;
 	arena->ptes[5] = 0;
+	*(vip)CIA_IOC_TBn_PAGEm(0,0) = 0;
+	*(vip)CIA_IOC_TB_TAGn(0) = 0;
 
 	if (use_tbia_try2) {
 		alpha_mv.mv_pci_tbi = cia_pci_tbi_try2;
@@ -760,6 +770,9 @@
 	hwrpb_update_checksum(hwrpb);
 
 	do_init_arch(1);
+	/* Normally, we should check for the presence of this bug,
+	 * but there's no easy way to detect it. KG, 2001-12-18. */
+	have_pyxis_pagecross_bug = 1;
 }
 
 void __init
--- linux-2.4.18.SuSE/arch/alpha/kernel/alpha_ksyms.c	Wed Mar 27 10:58:30 2002
+++ linux-2.4.18.SuSE.axp/arch/alpha/kernel/alpha_ksyms.c	Fri Apr  5 13:10:59 2002
@@ -263,7 +263,12 @@
 
 EXPORT_SYMBOL(get_wchan);
 
-#ifdef CONFIG_ALPHA_IRONGATE
+#if defined(CONFIG_ALPHA_CIA) || defined(CONFIG_ALPHA_GENERIC)
+extern int have_pyxis_pagecross_bug;
+EXPORT_SYMBOL_NOVERS(have_pyxis_pagecross_bug);
+#endif
+
+# ifdef CONFIG_ALPHA_IRONGATE
 EXPORT_SYMBOL(irongate_ioremap);
 EXPORT_SYMBOL(irongate_iounmap);
 #endif