Re: [patch 0/7] staging: speakup: migrate synths to use TTY-based comms

[Okash Khawaja <okash.khawaja@xxxxxxxxx>]

On Mon, Apr 03, 2017 at 09:21:23PM +0100, Okash Khawaja wrote:
> Hi,
> 
> This patchset migrates synths to use TTY-based comms instead of directly using
> serial i/o. The move doesn't cover those synths which do need direct access,
> e.g. some which talk over ISA.
> 
> Please note that this patchset applies on top of current staging-next branch of
> Greg Kroah-Hartman's tree as that contains some other changes to speakup and
> tty drivers that have recently gone in. So the first patch makes ammendments to
> TTY code which allows speakup to access and tty device. Next patch adds
> spk_ttyio.c which contains TTY-based initialisation and output functionality.
> Next patch migrates those synths which only use output: dummy, acntsa, bns and
> txprt. Then we add xchar and tiocmset functions. Next we rearrange the code
> such that input functionality is grouped under a few methods inside spk_synth
> and spk_io_ops structs. That paves the way for simple migration of other synths
> to TTY. The final patch does that for apollo, ltlk, audptr, decext, dectlk
> and spkout.
> 
> Thanks,
> Okash


Hi,

The staging-next tree wasn't working for me, specially the usb modules.
So I took following steps:

1. Switch to kernel versio 4.10.0 (I guess others upto 4.10.8 will be
fine)

2. Copy drivers/staging/speakup directory from staging-next tree to
overwrite the one in 4.10.0.

3. Use the patch I have attached as the first patch instead of the one
in this email series ([patch 1/7] staging: speakup: export
tty_open_by_driver).

4. Apply rest of the patches in this patchset.

That worked for me. As I have mentioned before, apollo and double talk
lt worked fine but I haven't done thorough testing. If you have
questions about applying patches, do let me know.

Thanks,
Okash

Index: linux-stable/drivers/tty/tty_io.c
===================================================================
--- linux-stable.orig/drivers/tty/tty_io.c
+++ linux-stable/drivers/tty/tty_io.c
@@ -855,7 +855,7 @@
 
 int tty_hung_up_p(struct file *filp)
 {
-	return (filp->f_op == &hung_up_tty_fops);
+	return (filp && filp->f_op == &hung_up_tty_fops);
 }
 
 EXPORT_SYMBOL(tty_hung_up_p);
@@ -1368,7 +1368,10 @@
 	struct tty_struct *tty;
 
 	if (driver->ops->lookup)
-		tty = driver->ops->lookup(driver, file, idx);
+		if (!file)
+			tty = ERR_PTR(-EIO);
+		else
+			tty = driver->ops->lookup(driver, file, idx);
 	else
 		tty = driver->ttys[idx];
 
@@ -1986,7 +1989,7 @@
 		struct tty_driver *console_driver = console_device(index);
 		if (console_driver) {
 			driver = tty_driver_kref_get(console_driver);
-			if (driver) {
+			if (driver && filp) {
 				/* Don't let /dev/console block */
 				filp->f_flags |= O_NONBLOCK;
 				break;
@@ -2019,7 +2022,7 @@
  *	  - concurrent tty driver removal w/ lookup
  *	  - concurrent tty removal from driver table
  */
-static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
+struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
 					     struct file *filp)
 {
 	struct tty_struct *tty;
@@ -2064,6 +2067,7 @@
 	tty_driver_kref_put(driver);
 	return tty;
 }
+EXPORT_SYMBOL(tty_open_by_driver);
 
 /**
  *	tty_open		-	open a tty device
Index: linux-stable/drivers/tty/tty_port.c
===================================================================
--- linux-stable.orig/drivers/tty/tty_port.c
+++ linux-stable/drivers/tty/tty_port.c
@@ -335,7 +335,7 @@
  *	tty_port_block_til_ready	-	Waiting logic for tty open
  *	@port: the tty port being opened
  *	@tty: the tty device being bound
- *	@filp: the file pointer of the opener
+ *	@filp: the file pointer of the opener or NULL
  *
  *	Implement the core POSIX/SuS tty behaviour when opening a tty device.
  *	Handles:
@@ -369,7 +369,7 @@
 		tty_port_set_active(port, 1);
 		return 0;
 	}
-	if (filp->f_flags & O_NONBLOCK) {
+	if (filp ==  NULL || filp->f_flags & O_NONBLOCK) {
 		/* Indicate we are open */
 		if (C_BAUD(tty))
 			tty_port_raise_dtr_rts(port);
Index: linux-stable/include/linux/tty.h
===================================================================
--- linux-stable.orig/include/linux/tty.h
+++ linux-stable/include/linux/tty.h
@@ -394,6 +394,8 @@
 /* tty_io.c */
 extern int __init tty_init(void);
 extern const char *tty_name(const struct tty_struct *tty);
+extern struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
+					     struct file *filp);
 #else
 static inline void console_init(void)
 { }

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