OMAP: DSS2: DSI: use a private workqueue
Using the shared workqueue led to to a deadlock in the case where the display was unblanked via keyboard. What happens is something like this: - User presses a key context 1: - drivers/char/keyboard.c calls schedule_console_callback() - fb_unblank takes the console semaphore - dsi bus lock is taken, and frame transfer is started (dsi bus lock is left on) - Unblank code tries to set the panel backlight, which tries to take dsi bus lock, but is blocked while the frame transfer is going on context 2, shared workqueue, console_callback in drivers/char/vt.c: - Tries to take console semaphore - Blocks, as console semaphore is being held by context 1 - No other shared workqueue work can be run context 3, HW irq, caused by FRAMEDONE interrupt: - Interrupt handler schedules framedone-work in shared workqueue - Framedone-work is never ran, as the shared workqueue is blocked. This means that the unblank thread stays blocked, which means that context 2 stays blocked. While I think the real problem is in keyboard/virtual terminal code, using a private workqueue in the DSI driver is perhaps safer and more robust than using the shared one. The DSI works should not be delayed more than a millisecond or so, and even if the private workqueue gives us no hard promise of doing so, it's still safer bet than the shared workqueue. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
This commit is contained in:
parent
86a7867ebf
commit
0f16aa0ae6
|
@ -238,6 +238,8 @@ static struct
|
|||
|
||||
bool te_enabled;
|
||||
|
||||
struct workqueue_struct *workqueue;
|
||||
|
||||
struct work_struct framedone_work;
|
||||
void (*framedone_callback)(int, void *);
|
||||
void *framedone_data;
|
||||
|
@ -2759,6 +2761,7 @@ static void dsi_update_screen_dispc(struct omap_dss_device *dssdev,
|
|||
unsigned packet_payload;
|
||||
unsigned packet_len;
|
||||
u32 l;
|
||||
int r;
|
||||
const unsigned channel = dsi.update_channel;
|
||||
/* line buffer is 1024 x 24bits */
|
||||
/* XXX: for some reason using full buffer size causes considerable TX
|
||||
|
@ -2809,8 +2812,9 @@ static void dsi_update_screen_dispc(struct omap_dss_device *dssdev,
|
|||
|
||||
dsi_perf_mark_start();
|
||||
|
||||
schedule_delayed_work(&dsi.framedone_timeout_work,
|
||||
r = queue_delayed_work(dsi.workqueue, &dsi.framedone_timeout_work,
|
||||
msecs_to_jiffies(250));
|
||||
BUG_ON(r == 0);
|
||||
|
||||
dss_start_update(dssdev);
|
||||
|
||||
|
@ -2841,6 +2845,11 @@ static void dsi_framedone_timeout_work_callback(struct work_struct *work)
|
|||
|
||||
DSSERR("Framedone not received for 250ms!\n");
|
||||
|
||||
/* XXX While extremely unlikely, we could get FRAMEDONE interrupt after
|
||||
* 250ms which would conflict with this timeout work. What should be
|
||||
* done is first cancel the transfer on the HW, and then cancel the
|
||||
* possibly scheduled framedone work */
|
||||
|
||||
/* SIDLEMODE back to smart-idle */
|
||||
dispc_enable_sidle();
|
||||
|
||||
|
@ -2873,6 +2882,7 @@ static void dsi_framedone_timeout_work_callback(struct work_struct *work)
|
|||
|
||||
static void dsi_framedone_irq_callback(void *data, u32 mask)
|
||||
{
|
||||
int r;
|
||||
/* Note: We get FRAMEDONE when DISPC has finished sending pixels and
|
||||
* turns itself off. However, DSI still has the pixels in its buffers,
|
||||
* and is sending the data.
|
||||
|
@ -2881,7 +2891,8 @@ static void dsi_framedone_irq_callback(void *data, u32 mask)
|
|||
/* SIDLEMODE back to smart-idle */
|
||||
dispc_enable_sidle();
|
||||
|
||||
schedule_work(&dsi.framedone_work);
|
||||
r = queue_work(dsi.workqueue, &dsi.framedone_work);
|
||||
BUG_ON(r == 0);
|
||||
}
|
||||
|
||||
static void dsi_handle_framedone(void)
|
||||
|
@ -3292,6 +3303,10 @@ int dsi_init(struct platform_device *pdev)
|
|||
mutex_init(&dsi.lock);
|
||||
sema_init(&dsi.bus_lock, 1);
|
||||
|
||||
dsi.workqueue = create_singlethread_workqueue("dsi");
|
||||
if (dsi.workqueue == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
INIT_WORK(&dsi.framedone_work, dsi_framedone_work_callback);
|
||||
INIT_DELAYED_WORK_DEFERRABLE(&dsi.framedone_timeout_work,
|
||||
dsi_framedone_timeout_work_callback);
|
||||
|
@ -3328,6 +3343,7 @@ int dsi_init(struct platform_device *pdev)
|
|||
err2:
|
||||
iounmap(dsi.base);
|
||||
err1:
|
||||
destroy_workqueue(dsi.workqueue);
|
||||
return r;
|
||||
}
|
||||
|
||||
|
@ -3335,6 +3351,8 @@ void dsi_exit(void)
|
|||
{
|
||||
iounmap(dsi.base);
|
||||
|
||||
destroy_workqueue(dsi.workqueue);
|
||||
|
||||
DSSDBG("omap_dsi_exit\n");
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue