Patch from Anders Blomdell: "When uppgrading to 2.6.26.3, I found out that

f->f_op->ioctl is NULL with some (all?) serial drivers. Changing to
f->f_op->unlocked_ioctl worked for everything except FIONREAD, which
occasionally page faulted, hence I use 'settings.c_cc[VMIN] = 0
settings.c_cc[VTIME] = 0;' and use f->f_op->read for polling.

diff --git a/comedi/drivers/serial2002.c b/comedi/drivers/serial2002.c
index b6a0d89a1ade61bc57e6842bfec726a59330d48a..924d953205d094326368466027cd6f66a357dd86 100644 (file)
--- a/comedi/drivers/serial2002.c
+++ b/comedi/drivers/serial2002.c
@@ -114,6 +114,19 @@ struct serial_data {
        unsigned long value;
 };
 
+static long tty_ioctl(struct file *f, unsigned op, unsigned long param) 
+{
+#ifdef HAVE_UNLOCKED_IOCTL
+       if (f->f_op->unlocked_ioctl) {
+               return f->f_op->unlocked_ioctl(f, op, param);
+       }
+#endif    
+       if (f->f_op->ioctl) {
+               return f->f_op->ioctl(f->f_dentry->d_inode, f, op, param);
+       }
+       return -ENOSYS;
+}
+
 static int tty_write(struct file *f, unsigned char *buf, int count)
 {
        int result;
@@ -127,6 +140,11 @@ static int tty_write(struct file *f, unsigned char *buf, int count)
        return result;
 }
 
+#if 0
+/* 
+ * On 2.6.26.3 this occaisonally gave me page faults, worked around by
+ * settings.c_cc[VMIN] = 0; settings.c_cc[VTIME] = 0
+ */
 static int tty_available(struct file *f)
 {
        long result = 0;
@@ -134,11 +152,11 @@ static int tty_available(struct file *f)
 
        oldfs = get_fs();
        set_fs(KERNEL_DS);
-       f->f_op->ioctl(f->f_dentry->d_inode, f, FIONREAD,
-               (unsigned long)&result);
+       tty_ioctl(f, FIONREAD, (unsigned long)&result);
        set_fs(oldfs);
        return result;
 }
+#endif 
 
 static int tty_read(struct file *f, int timeout)
 {
@@ -177,28 +195,33 @@ static int tty_read(struct file *f, int timeout)
                                                        elapsed) * HZ) / 10000);
                        }
                        poll_freewait(&table);
+                       {
+                         unsigned char ch;
+                         
+                         f->f_pos = 0;
+                         if (f->f_op->read(f, &ch, 1, &f->f_pos) == 1) {
+                           result = ch;
+                         }
+                       }
                } else {
                        /* Device does not support poll, busy wait */
                        int retries = 0;
                        while (1) {
+                               unsigned char ch;
+                               
                                retries++;
                                if (retries >= timeout) {
                                        break;
                                }
-                               if (tty_available(f) > 0) {
+                         
+                               f->f_pos = 0;
+                               if (f->f_op->read(f, &ch, 1, &f->f_pos) == 1) {
+                                       result = ch;
                                        break;
                                }
                                comedi_udelay(100);
                        }
                }
-               if (tty_available(f) > 0) {
-                       unsigned char ch;
-
-                       f->f_pos = 0;
-                       if (f->f_op->read(f, &ch, 1, &f->f_pos) == 1) {
-                               result = ch;
-                       }
-               }
                set_fs(oldfs);
        }
        return result;
@@ -214,14 +237,13 @@ static void tty_setspeed(struct file *f, int speed)
                // Set speed
                struct termios settings;
 
-               f->f_op->ioctl(f->f_dentry->d_inode, f, TCGETS,
-                       (unsigned long)&settings);
+               tty_ioctl(f, TCGETS, (unsigned long)&settings);
 //    printk("Speed: %d\n", settings.c_cflag & (CBAUD | CBAUDEX));
                settings.c_iflag = 0;
                settings.c_oflag = 0;
                settings.c_lflag = 0;
                settings.c_cflag = CLOCAL | CS8 | CREAD;
-               settings.c_cc[VMIN] = 1;
+               settings.c_cc[VMIN] = 0;
                settings.c_cc[VTIME] = 0;
                switch (speed) {
                case 2400:{
@@ -257,18 +279,16 @@ static void tty_setspeed(struct file *f, int speed)
                        }
                        break;
                }
-               f->f_op->ioctl(f->f_dentry->d_inode, f, TCSETS,
-                       (unsigned long)&settings);
+               tty_ioctl(f, TCSETS, (unsigned long)&settings);
 //    printk("Speed: %d\n", settings.c_cflag & (CBAUD | CBAUDEX));
        }
        {
                // Set low latency
                struct serial_struct settings;
-               f->f_op->ioctl(f->f_dentry->d_inode, f, TIOCGSERIAL,
-                       (unsigned long)&settings);
+
+               tty_ioctl(f, TIOCGSERIAL, (unsigned long)&settings);
                settings.flags |= ASYNC_LOW_LATENCY;
-               f->f_op->ioctl(f->f_dentry->d_inode, f, TIOCSSERIAL,
-                       (unsigned long)&settings);
+               tty_ioctl(f, TIOCSSERIAL, (unsigned long)&settings);
        }
 
        set_fs(oldfs);
@@ -820,8 +840,6 @@ static int serial2002_attach(comedi_device * dev, comedi_devconfig * it)
        s->range_table = 0;
        s->insn_read = &serial2002_ei_rinsn;
 
-       printk("attached\n");
-
        return 1;
 }