touch: synaptics_tcm: fix race condition between touch isr and resume

During touch resume for the first time, syna_tcm_identify times out when
expected syna_tcm_isr does not come. ISR does not come due to previous
pending ISR. Previous ISR is waiting for mutex lock mod_pool.mutex which
is acquired in syna_tcm_resume function leading to deadlock till timeout.

To fix this, early return from syna_tcm_isr if it is unable to acquire
mod_pool.mutex.

Change-Id: I18be302edfb19270014610451dda97331d78049f
Signed-off-by: Ritesh Kumar <[email protected]>

synaptics_tcm/synaptics_tcm_core.c

@@ -629,7 +629,12 @@ static void syna_tcm_dispatch_report(struct syna_tcm_hcd *tcm_hcd)
 
 	tcm_hcd->report.id = tcm_hcd->status_report_code;
 
-	mutex_lock(&mod_pool.mutex);
+	if (!mutex_trylock(&mod_pool.mutex)) {
+		LOGI(tcm_hcd->pdev->dev.parent, "unable to acquire mod_pool.mutex\n");
+		UNLOCK_BUFFER(tcm_hcd->report.buffer);
+		UNLOCK_BUFFER(tcm_hcd->in);
+		return;
+	}
 
 	if (!list_empty(&mod_pool.list)) {
 		list_for_each_entry(mod_handler, &mod_pool.list, link) {