Linux Device Drivers

Errata for Linux Device Drivers

Submit your own errata for this product.


The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color Key: Serious Technical Mistake Minor Technical Mistake Language or formatting error Typo Question Note Update



Version Location Description Submitted By Date Submitted Date Corrected
Printed
Page xv
last paragraph

Original href to http://www.linuxdoc.org has now become out of date. The new href is http://www.tldp.org (The Linux Documentation Project)

Anonymous   
Printed
Page 27
the line in Rules.make file

ifeq ($(KERNELDIR)/.config,$(wildcard $(KERNELDIR))/.config) Should be: ^ ifeq ($(KERNELDIR)/.config,$(wildcard $(KERNELDIR)/.config)) ^

Anonymous   
Printed
Page 32
in init_module(void)

Currently the first if statement in the functions reads: if(!item2 || !item2) Should be changed to if(!item1 || !item2)

Anonymous   
Printed
Page 88
The first example of code

In the second edition of yours "Linux Device Drivers" book there is an example of supporting devfs in the module code. The excerpt from ldd2-samples-1.0.1/scull/main.c (the int scull_init_module(void)) looks like: #ifdef CONFIG_DEVFS_FS sprintf(devname, "%i", i); devfs_register(scull_devfs_dir, devname, DEVFS_FL_AUTO_DEVNUM, 0, 0, S_IFCHR | S_IRUGO | S_IWUGO, &scull_fops, scull_devices+i); #endif But the devfs_register doesn't know the format of the structure Scull_Dev, so it can't initialize the member 'handle' in it ( (scull_devices+i)->handle), so it remains uninitialized. In the scull_cleanup_module(void) there is explicit use of an uninitialized handle (due to the fact scull_devices members are initialized by zeroes this just do nothing): devfs_unregister(scull_devices[i].handle); So it means, the scull_devices[i].handle __must__ be initialized correctly to unregister a device. So the "fix" is just like: #ifdef CONFIG_DEVFS_FS sprintf(devname, "%i", i); scull_devices[i].handle = devfs_register(scull_devfs_dir, devname, DEVFS_FL_AUTO_DEVNUM, 0, 0, S_IFCHR | S_IRUGO | S_IWUGO, &scull_fops, scull_devices+i); #endif

Anonymous   
Printed
Page 94
1st paragraph, last line.

SET_FILE_OWNER should be SET_MODULE_OWNER.

Anonymous   
Printed
Page 151
Last Paragraph

Last paragraph of Pg 151 : 'The if statement that follows interruptible_sleep_on takes care of signal handling.' should be: 'The if statement that follows wait_event_interruptible takes care of signal handling.'

Anonymous   
Printed
Page 206
Description of DECLARE_TASK_QUEUE.

It should read something like: This macro declares a new task queue named variablename and initializes it.

Anonymous   
Printed
Page 231
Second line from the bottom.

"or" should be "of"

Anonymous   
Printed
Page 247
Middle of page, code for probing expansion ROM.

add += (size & ~2048) - 2048; /* skip it */ should be add += (size + 2047) & ~2047; /* skip it */

Anonymous   
Printed
Page 282
In the second edition (June 2001) of your book, Linux Device

Drivers (ISBN 0-596-00008-1), on page 282 under the description of "spin_trylock" I see: "To attempt to acquire a lock without waiting, use spin_trylock, which returns nonzero if the operation failed (the lock was busy)." This is, in fact, false. The return value is zero when the operation fails and nonzero when it succeeds.

Anonymous   
Printed
Page 286

it states that atomic_inc_and_test (and other functions) return the "previous" value of the atomic data type. In the 2.4 source code, the comments claim that the value returned is either TRUE if the "new" value of the data type is zero, or FALSE otherwise. (Which makes these routines fairly useless, but...)

Anonymous   
Printed
Page 287
Second-to-last paragraph, second sentence

The text states "The current state is set to TASK_RUNNING to reflect the fact that we are no longer asleep; this is necessary because if we exited the loop without ever sleeping, we may still be in TASK_INTERRUPTIBLE." it should say: "The current state is set to TASK_RUNNING to reflect the fact that we are no longer asleep; this is necessary because when we exit the loop <tty>current->state</tty> will be TASK_INTERRUPTIBLE. (Although after schedule() returns the process is always in TASK_RUNNING).

Anonymous   
Printed
Page 358
Paragraph 2 and following 2 lines of code.

Seems this interface changed early in 2.4. From genhd.c: /* * Global kernel list of partitioning information. * * XXX: you should _never_ access this directly. * the only reason this is exported is source compatiblity. */ /*static*/ struct gendisk *gendisk_head; static struct gendisk *gendisk_array[MAX_BLKDEV]; static rwlock_t gendisk_lock = RW_LOCK_UNLOCKED; /** * add_gendisk - add partitioning information to kernel list * @gp: per-device partitioning information * * This function registers the partitioning information in @gp * with the kernel. */ void add_gendisk(struct gendisk *gp) If you want to do this by hand, you should be holding gendisk_lock. AUTHOR: The author is right that the add_gendisk() and del_gendisk() functions were added after the book came out - in 2.4.10, actually. I have no objection to adding them to the errata so that people know about them. The method described in the book still works - for 2.4 - however. It all breaks in 2.5, of course.

Anonymous   
Printed
Page 390
1st paragraph

last line of example -- remap_page_range(vma_->vm_start... should be remap_page_range(vma->vm_start...

Anonymous   
Printed
Page 407
Prototype of pci_free_consistent()

The type of the last argument should be dma_addr_t. AUTHOR: Right. Same applies to page 409 and the two entries in the reference at the end of the chapter.

Anonymous   
Printed
Page 434
2nd paragraph

kfree( snull_devs[i].priv) is called before unregister_netdev(). But unregister_netdev is later calling the snull_stats() function once again that accesses snull[devs].priv. This may lead to a segmentation fault. Detected on uClinux-2.4.20 AUTHOR: The solution is to reverse the two lines in snull_cleanup: void snull_cleanup(void) { int i; for (i=0; i<2; i++) { unregister_netdev(snull_devs + i); kfree(snull_devs[i].priv); } return; }

Anonymous   
Printed
Page 453
3rd paragraph

ether_type_trans should be eth_type_trans

Anonymous   
Printed
Page 455
last paragraph

dev->addr should be dev->dev_addr

Anonymous   
Printed
Page 475
2nd paragraph, line 1.

"address" Would be clearer as: "configuration"

Anonymous   
Printed
Page 481
2nd code sample

unsigned char jail_get_revision(unsigned char bus, unsigned char fn) { unsigned char *revision; pci_read_config_byte(bus, fn, PCI_REVISION_ID, &revision); return revision; } Should be: unsigned char jail_get_revision(struct pci_dev *dev) { unsigned char revision; pci_read_config_byte(dev, PCI_REVISION_ID, &revision); return revision; }

Anonymous   
Printed
Page 483
First paragraph.

Since pcidata.c is GPLed, it should include MODULE_LICENSE("GPL"); to avoid the taint warning from recent 2.4 kernels. AUTHOR'S NOTE: "Errata" is perhaps the wrong word; MODULE_LICENSE was introduced in 2.4.10, and so came well after the publication of the book. And, of course, the module will work just as well without the license declaration. I have no objection to adding it to the list, though; all modules should have a MODULE_LICENSE line in them now.

Anonymous   
Printed
Page 488
paragraph 3, line 2

pci_resource_size should be pci_resource_len

Anonymous   
Printed
Page 504
Middle.

The third argument to the three pci_write_config_*() functions should be integer types, not point ers to these types. int pci_write_config_byte (struct pci_dev *dev, int where, u8 *val); int pci_write_config_word (struct pci_dev *dev, int where, u16 *val); int pci_write_config_dword (struct pci_dev *dev, int where, u32 *val); Should be: int pci_write_config_byte (struct pci_dev *dev, int where, u8 val); int pci_write_config_word (struct pci_dev *dev, int where, u16 val); int pci_write_config_dword (struct pci_dev *dev, int where, u32 val);

Anonymous