From: Dmitry Torokhov Date: Mon, 25 Jul 2016 18:36:54 +0000 (-0700) Subject: Input: i8042 - break load dependency between atkbd/psmouse and i8042 X-Git-Tag: v3.2.84~111 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=538cff0a1a08d5bc658351c2cc35456205b5ff92 Input: i8042 - break load dependency between atkbd/psmouse and i8042 commit 4097461897df91041382ff6fcd2bfa7ee6b2448c upstream. As explained in 1407814240-4275-1-git-send-email-decui@microsoft.com we have a hard load dependency between i8042 and atkbd which prevents keyboard from working on Gen2 Hyper-V VMs. > hyperv_keyboard invokes serio_interrupt(), which needs a valid serio > driver like atkbd.c. atkbd.c depends on libps2.c because it invokes > ps2_command(). libps2.c depends on i8042.c because it invokes > i8042_check_port_owner(). As a result, hyperv_keyboard actually > depends on i8042.c. > > For a Generation 2 Hyper-V VM (meaning no i8042 device emulated), if a > Linux VM (like Arch Linux) happens to configure CONFIG_SERIO_I8042=m > rather than =y, atkbd.ko can't load because i8042.ko can't load(due to > no i8042 device emulated) and finally hyperv_keyboard can't work and > the user can't input: https://bugs.archlinux.org/task/39820 > (Ubuntu/RHEL/SUSE aren't affected since they use CONFIG_SERIO_I8042=y) To break the dependency we move away from using i8042_check_port_owner() and instead allow serio port owner specify a mutex that clients should use to serialize PS/2 command stream. Reported-by: Mark Laws Tested-by: Mark Laws Signed-off-by: Dmitry Torokhov Signed-off-by: Ben Hutchings --- diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c index 178e75d6bb06..514553ba810d 100644 --- a/drivers/input/serio/i8042.c +++ b/drivers/input/serio/i8042.c @@ -1223,6 +1223,7 @@ static int __init i8042_create_kbd_port(void) serio->start = i8042_start; serio->stop = i8042_stop; serio->close = i8042_port_close; + serio->ps2_cmd_mutex = &i8042_mutex; serio->port_data = port; serio->dev.parent = &i8042_platform_device->dev; strlcpy(serio->name, "i8042 KBD port", sizeof(serio->name)); @@ -1310,21 +1311,6 @@ static void __devexit i8042_unregister_ports(void) } } -/* - * Checks whether port belongs to i8042 controller. - */ -bool i8042_check_port_owner(const struct serio *port) -{ - int i; - - for (i = 0; i < I8042_NUM_PORTS; i++) - if (i8042_ports[i].serio == port) - return true; - - return false; -} -EXPORT_SYMBOL(i8042_check_port_owner); - static void i8042_free_irqs(void) { if (i8042_aux_irq_registered) diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c index 07a8363f3c5c..b5ec313cb9c9 100644 --- a/drivers/input/serio/libps2.c +++ b/drivers/input/serio/libps2.c @@ -57,19 +57,17 @@ EXPORT_SYMBOL(ps2_sendbyte); void ps2_begin_command(struct ps2dev *ps2dev) { - mutex_lock(&ps2dev->cmd_mutex); + struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; - if (i8042_check_port_owner(ps2dev->serio)) - i8042_lock_chip(); + mutex_lock(m); } EXPORT_SYMBOL(ps2_begin_command); void ps2_end_command(struct ps2dev *ps2dev) { - if (i8042_check_port_owner(ps2dev->serio)) - i8042_unlock_chip(); + struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; - mutex_unlock(&ps2dev->cmd_mutex); + mutex_unlock(m); } EXPORT_SYMBOL(ps2_end_command); diff --git a/include/linux/i8042.h b/include/linux/i8042.h index a986ff588944..801c307f6fcc 100644 --- a/include/linux/i8042.h +++ b/include/linux/i8042.h @@ -38,7 +38,6 @@ struct serio; void i8042_lock_chip(void); void i8042_unlock_chip(void); int i8042_command(unsigned char *param, int command); -bool i8042_check_port_owner(const struct serio *); int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str, struct serio *serio)); int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str, @@ -59,11 +58,6 @@ static inline int i8042_command(unsigned char *param, int command) return -ENODEV; } -static inline bool i8042_check_port_owner(const struct serio *serio) -{ - return false; -} - static inline int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str, struct serio *serio)) { diff --git a/include/linux/serio.h b/include/linux/serio.h index ca82861b0e46..34b403a6d284 100644 --- a/include/linux/serio.h +++ b/include/linux/serio.h @@ -33,7 +33,8 @@ struct serio { struct serio_device_id id; - spinlock_t lock; /* protects critical sections from port's interrupt handler */ + /* Protects critical sections from port's interrupt handler */ + spinlock_t lock; int (*write)(struct serio *, unsigned char); int (*open)(struct serio *); @@ -42,16 +43,29 @@ struct serio { void (*stop)(struct serio *); struct serio *parent; - struct list_head child_node; /* Entry in parent->children list */ + /* Entry in parent->children list */ + struct list_head child_node; struct list_head children; - unsigned int depth; /* level of nesting in serio hierarchy */ + /* Level of nesting in serio hierarchy */ + unsigned int depth; - struct serio_driver *drv; /* accessed from interrupt, must be protected by serio->lock and serio->sem */ - struct mutex drv_mutex; /* protects serio->drv so attributes can pin driver */ + /* + * serio->drv is accessed from interrupt handlers; when modifying + * caller should acquire serio->drv_mutex and serio->lock. + */ + struct serio_driver *drv; + /* Protects serio->drv so attributes can pin current driver */ + struct mutex drv_mutex; struct device dev; struct list_head node; + + /* + * For use by PS/2 layer when several ports share hardware and + * may get indigestion when exposed to concurrent access (i8042). + */ + struct mutex *ps2_cmd_mutex; }; #define to_serio_port(d) container_of(d, struct serio, dev)