Em Sat, 23 May 2009 14:06:01 +0200
AH <andrzej.hajda@xxxxx> escreveu:
> Hi
>
> Some remotes requires short polling interval which in modern kernels is
> below resolution of standard scheduler (schedule_delayed_work), this
> causes problem of missed keystrokes. One of the solutions is to raise
> kernel timer frequency, my proposition is to use high resolution timers
> which are present in kernel since 2.6.16 (at least API AFAIK).
> I have encountered this problem on my Winfast 2000XP Expert, but after
> checking cx88-input.c it seems that following cards can be affected also:
> WINFAST2000XP_EXPERT
> WINFAST_DTV1000
> WINFAST_TV2000_XP_GLOBAL
> PROLINK_PLAYTVPVR
> PIXELVIEW_PLAYTV_ULTRA_PRO
> PROLINK_PV_8000GT
> PROLINK_PV_GLOBAL_XTREME
> KWORLD_LTV883
> MSI_TVANYWHERE_MASTER
>
> Patched driver seems to work on my system, with kernel 2.6.28.
> I have removed kernel checks for versions below 2.6.20 - they were
> because of API changes in scheduler.
>
> I have not tested it on older kernels.
>
> Regards
> AH
>
> diff -r 315bc4b65b4f linux/drivers/media/video/cx88/cx88-input.c
> --- a/linux/drivers/media/video/cx88/cx88-input.c Sun May 17
> 12:28:55 2009 +0000
> +++ b/linux/drivers/media/video/cx88/cx88-input.c Sat May 23
> 14:04:17 2009 +0200
> @@ -23,10 +23,10 @@
> */
>
> #include <linux/init.h>
> -#include <linux/delay.h>
> #include <linux/input.h>
> #include <linux/pci.h>
> #include <linux/module.h>
> +#include <linux/hrtimer.h>
>
> #include "compat.h"
> #include "cx88.h"
> @@ -49,7 +49,7 @@
>
> /* poll external decoder */
> int polling;
> - struct delayed_work work;
> + struct hrtimer timer;
> u32 gpio_addr;
> u32 last_gpio;
> u32 mask_keycode;
> @@ -144,31 +144,25 @@
> }
> }
>
> -#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
> -static void cx88_ir_work(void *data)
> -#else
> -static void cx88_ir_work(struct work_struct *work)
> -#endif
> +enum hrtimer_restart cx88_ir_work(struct hrtimer *timer)
> {
> -#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
> - struct cx88_IR *ir = data;
> -#else
> - struct cx88_IR *ir = container_of(work, struct cx88_IR, work.work);
> -#endif
> + unsigned long missed;
> + struct cx88_IR *ir = container_of(timer, struct cx88_IR, timer);
>
> cx88_ir_handle_key(ir);
> - schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
> + missed = hrtimer_forward_now(&ir->timer, ktime_set(0,
> ir->polling * 1000000));
Hmm... this patch got line wrapped. please fix it and re-send.
> + if (missed > 1)
> + ir_dprintk("Missed ticks %ld\n", missed - 1);
> +
> + return HRTIMER_RESTART;
> }
>
> void cx88_ir_start(struct cx88_core *core, struct cx88_IR *ir)
> {
> if (ir->polling) {
> -#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
> - INIT_DELAYED_WORK(&ir->work, cx88_ir_work, ir);
> -#else
> - INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
> -#endif
> - schedule_delayed_work(&ir->work, 0);
> + hrtimer_init(&ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> + ir->timer.function = cx88_ir_work;
> + hrtimer_start(&ir->timer, ktime_set(0, ir->polling *
> 1000000), HRTIMER_MODE_REL);
> }
> if (ir->sampling) {
> core->pci_irqmask |= PCI_INT_IR_SMPINT;
> @@ -185,7 +179,7 @@
> }
>
> if (ir->polling)
> - cancel_delayed_work_sync(&ir->work);
> + hrtimer_cancel(&ir->timer);
> }
>
> /*
> ---------------------------------------------------------------------- */
>
> --
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Cheers,
Mauro
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