[PATCH 5/7] HID: picoLCD: Improve unplug handling

From: Bruno PrÃmont
Date: Mon Jul 30 2012 - 15:39:32 EST


Stop earlier attempting to submit new reports/URBs (though locking and
usbhid still prevents to bail out early enough to not produce multiple
hid-picolcd 0003:04D8:C002.0003: usb_submit_urb(out) failed: -19
messages in kernel log.

Strengthen framebuffer removal to be less racy, though quick
bind/unbind sequences triggered via sysfs still trigger weird behavior:
- either SLAB corruptions
Seems related to fbdefio
- immediate system reboot
Unexplained as there is no explaining output on any console, not even
serial console.
(note: picoLCD is hosting fbcon in both cases, but manual plug/unplug
seems too slow to trigger madness)

Signed-off-by: Bruno PrÃmont <bonbons@xxxxxxxxxxxxxxxxx>
---
drivers/hid/hid-picolcd_backlight.c | 3 +-
drivers/hid/hid-picolcd_core.c | 21 ++++++++++++-----
drivers/hid/hid-picolcd_fb.c | 41 +++++++++++++++++++++-------------
drivers/hid/hid-picolcd_lcd.c | 3 +-
drivers/hid/hid-picolcd_leds.c | 3 +-
5 files changed, 46 insertions(+), 25 deletions(-)

diff --git a/drivers/hid/hid-picolcd_backlight.c b/drivers/hid/hid-picolcd_backlight.c
index cd1ccd7..b91f309 100644
--- a/drivers/hid/hid-picolcd_backlight.c
+++ b/drivers/hid/hid-picolcd_backlight.c
@@ -45,7 +45,8 @@ static int picolcd_set_brightness(struct backlight_device *bdev)
data->lcd_power = bdev->props.power;
spin_lock_irqsave(&data->lock, flags);
hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
- usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+ if (!(data->status & PICOLCD_FAILED))
+ usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
diff --git a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
index 8d5d341..2d7ef68 100644
--- a/drivers/hid/hid-picolcd_core.c
+++ b/drivers/hid/hid-picolcd_core.c
@@ -105,12 +105,17 @@ struct picolcd_pending *picolcd_send_and_wait(struct hid_device *hdev,
hid_set_field(report->field[i], j, k < size ? raw_data[k] : 0);
k++;
}
- data->pending = work;
- usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
- spin_unlock_irqrestore(&data->lock, flags);
- wait_for_completion_interruptible_timeout(&work->ready, HZ*2);
- spin_lock_irqsave(&data->lock, flags);
- data->pending = NULL;
+ if (data->status & PICOLCD_FAILED) {
+ kfree(work);
+ work = NULL;
+ } else {
+ data->pending = work;
+ usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+ spin_unlock_irqrestore(&data->lock, flags);
+ wait_for_completion_interruptible_timeout(&work->ready, HZ*2);
+ spin_lock_irqsave(&data->lock, flags);
+ data->pending = NULL;
+ }
spin_unlock_irqrestore(&data->lock, flags);
mutex_unlock(&data->mutex);
return work;
@@ -235,6 +240,10 @@ int picolcd_reset(struct hid_device *hdev)

/* perform the reset */
hid_set_field(report->field[0], 0, 1);
+ if (data->status & PICOLCD_FAILED) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ return -ENODEV;
+ }
usbhid_submit_report(hdev, report, USB_DIR_OUT);
spin_unlock_irqrestore(&data->lock, flags);

diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c
index 602786c..4d8e22c 100644
--- a/drivers/hid/hid-picolcd_fb.c
+++ b/drivers/hid/hid-picolcd_fb.c
@@ -226,13 +226,16 @@ int picolcd_fb_reset(struct picolcd_data *data, int clear)
}

/* Update fb_vbitmap from the screen_base and send changed tiles to device */
-static void picolcd_fb_update(struct picolcd_data *data)
+static void picolcd_fb_update(struct fb_info *info)
{
int chip, tile, n;
unsigned long flags;
+ struct picolcd_data *data;

+ mutex_lock(&info->lock);
+ data = info->par;
if (!data)
- return;
+ goto out;

spin_lock_irqsave(&data->lock, flags);
if (!(data->status & PICOLCD_READY_FB)) {
@@ -256,17 +259,31 @@ static void picolcd_fb_update(struct picolcd_data *data)
data->fb_bitmap, data->fb_bpp, chip, tile) ||
data->fb_force) {
n += 2;
- if (data->status & PICOLCD_FAILED)
- return; /* device lost! */
if (n >= HID_OUTPUT_FIFO_SIZE / 2) {
+ mutex_unlock(&info->lock);
usbhid_wait_io(data->hdev);
+ mutex_lock(&info->lock);
+ data = info->par;
+ if (!data)
+ goto out;
+ spin_lock_irqsave(&data->lock, flags);
+ if (data->status & PICOLCD_FAILED) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ goto out;
+ }
+ spin_unlock_irqrestore(&data->lock, flags);
n = 0;
}
picolcd_fb_send_tile(data->hdev, chip, tile);
}
data->fb_force = false;
- if (n)
+ if (n) {
+ mutex_unlock(&info->lock);
usbhid_wait_io(data->hdev);
+ return;
+ }
+out:
+ mutex_unlock(&info->lock);
}

/* Stub to call the system default and update the image on the picoLCD */
@@ -327,17 +344,12 @@ static int picolcd_fb_blank(int blank, struct fb_info *info)

static void picolcd_fb_destroy(struct fb_info *info)
{
- struct picolcd_data *data;
-
/* make sure no work is deferred */
- cancel_delayed_work_sync(&info->deferred_work);
- data = info->par;
- info->par = NULL;
- if (data)
- data->fb_info = NULL;
+ fb_deferred_io_cleanup(info);

vfree((u8 *)info->fix.smem_start);
framebuffer_release(info);
+ printk(KERN_DEBUG "picolcd_fb_destroy(%p)\n", info);
}

static int picolcd_fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
@@ -425,7 +437,7 @@ static struct fb_ops picolcdfb_ops = {
/* Callback from deferred IO workqueue */
static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagelist)
{
- picolcd_fb_update(info->par);
+ picolcd_fb_update(info);
}

static const struct fb_deferred_io picolcd_fb_defio = {
@@ -582,10 +594,7 @@ void picolcd_exit_framebuffer(struct picolcd_data *data)
return;

device_remove_file(&data->hdev->dev, &dev_attr_fb_update_rate);
- mutex_lock(&info->lock);
- fb_deferred_io_cleanup(info);
info->par = NULL;
- mutex_unlock(&info->lock);
unregister_framebuffer(info);
data->fb_vbitmap = NULL;
data->fb_bitmap = NULL;
diff --git a/drivers/hid/hid-picolcd_lcd.c b/drivers/hid/hid-picolcd_lcd.c
index 64a067f..2d0ddc5 100644
--- a/drivers/hid/hid-picolcd_lcd.c
+++ b/drivers/hid/hid-picolcd_lcd.c
@@ -47,7 +47,8 @@ static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
data->lcd_contrast = contrast & 0x0ff;
spin_lock_irqsave(&data->lock, flags);
hid_set_field(report->field[0], 0, data->lcd_contrast);
- usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+ if (!(data->status & PICOLCD_FAILED))
+ usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
diff --git a/drivers/hid/hid-picolcd_leds.c b/drivers/hid/hid-picolcd_leds.c
index 5573cd8..28cb6a4 100644
--- a/drivers/hid/hid-picolcd_leds.c
+++ b/drivers/hid/hid-picolcd_leds.c
@@ -54,7 +54,8 @@ void picolcd_leds_set(struct picolcd_data *data)

spin_lock_irqsave(&data->lock, flags);
hid_set_field(report->field[0], 0, data->led_state);
- usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+ if (!(data->status & PICOLCD_FAILED))
+ usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
spin_unlock_irqrestore(&data->lock, flags);
}

--
1.7.8.6

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