On 12/10/23 13:42, Helge Deller wrote:
[ ... ]> I actually don't know if null-bytes are transferred.
But ext4 reports CRC errors, so I added this hunk to the Linux kernel:
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d7732320431a..9b12fbd44e06 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4732,6 +4736,9 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
if (ret < 0)
goto bad_inode;
raw_inode = ext4_raw_inode(&iloc);
+// printk("raw_info provided %px %x\n", &raw_inode->i_checksum_lo, raw_inode->i_checksum_lo);
+// printk(" iloc->bh->b_data %px iloc->offset %lx\n", iloc.bh->b_data, iloc.offset);
+if (raw_inode->i_checksum_lo == 0) asm(".word 0xfffdead0");
The last line immediately stops qemu if the checksum is zero.
I start qemu with
./qemu-system-hppa -drive file=../qemu-images/hdd.img.new,if=none,id=d0 -kernel vmlinux -append "root=/dev/sda5 console=ttyS0 single earlycon=pdc" -serial mon:stdio -smp cpus=3 -machine C3700 -nographic -snapshot -device am53c974,id=scsi -device scsi-hd,bus=scsi.0,drive=d0
qemu aborts with the am53c974 driver.
If I use exactly the same command, but with the lsi53c895a driver instead of am53c974, it boots correctly.
Any other idea?
Does your code use scatter-gather DMA ? If so, that might explain the problem.
I don't think the qemu code implements that properly. I don't mean the MDL version,
that isn't implemented at all. I mean the non-MDL version, where a single SCSI
command requires multiple DMA transfers which have to be set up one by one.
Guenter
