Hi Tarun, On Tue, Sep 20, 2011 at 6:30 AM, Tarun Kanti DebBarma <tarun.kanti@xxxxxx> wrote: > Clock is enabled only when timer is started and disabled when the the timer > is stopped. Therefore before accessing registers in functions clock is enabled > and then disabled back at the end of access. Context save is done dynamically > whenever the registers are modified. Context restore is called when context is > lost. Now that handling of the clock has been decoupled from omap_dm_timer_request_specific/free and placed in start/stop functions, there is a "possible irq lock inversion dependency detected" for any attempt to enable the clock from soft|hard irq. My use case is as follows: DSP sends a mailbox message to ARM, this triggers a tasklet in mailbox for processing the message, when it reaches tidspbridge it turns out that the DSP wants to enable a gpt timer; however, locks involved "clocks_mutex" and "dm_timer_lock" now could cause a deadlock as they have been called from unsafe contexts in the past (http://pastebin.com/7Dtz8t0f). Is the intention to restrict enabling the dmtimer clocks from hard|soft irqs? ... > @@ -303,6 +342,22 @@ void omap_dm_timer_stop(struct omap_dm_timer *timer) > rate = clk_get_rate(timer->fclk); > > __omap_dm_timer_stop(timer, timer->posted, rate, is_omap2); > + > + if (timer->loses_context) { > + if (timer->get_context_loss_count) > + timer->ctx_loss_count = > + timer->get_context_loss_count(&timer->pdev->dev); > + } > + > + /* > + * Since the register values are computed and written within > + * __omap_dm_timer_stop, we need to use read to retrieve the > + * context. > + */ > + timer->context.tclr = > + omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); > + timer->context.tisr = __raw_readl(timer->irq_stat); > + omap_dm_timer_disable(timer); > } > EXPORT_SYMBOL_GPL(omap_dm_timer_stop); > I didn't review the whole patch, but at least this part is not in mainline, it seems like the patch modified by Tony and the v16 were not the same. I could diff and include the missing parts, if someone can confirm that we need v16, which I believe so, since current stop function doesn't call omap_dm_timer_disable. Regards, Omar -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
