Commit-ID: 3a2c16c8489d967de10b3b7f5cc0f7cab4337770 Gitweb: http://git.kernel.org/tip/3a2c16c8489d967de10b3b7f5cc0f7cab4337770 Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Thu, 25 Jun 2015 18:44:03 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 6 Jul 2015 15:23:27 +0200 x86/asm/tsc, staging/lirc_serial: Remove TSC-based timing It wasn't compiled in by default. I suspect that the driver was and still is broken, though -- it's calling udelay with a parameter that's derived from loops_per_jiffy. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Huang Rui <ray.huang@xxxxxxx> Cc: Jarod Wilson <jarod@xxxxxxxxxxxx> Cc: John Stultz <john.stultz@xxxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: devel@xxxxxxxxxxxxxxxxxxxx Cc: kvm ML <kvm@xxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/c95df47c5405b494d19d20b2852a9378c9f661f3.1434501121.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- drivers/staging/media/lirc/lirc_serial.c | 63 ++------------------------------ 1 file changed, 4 insertions(+), 59 deletions(-) diff --git a/drivers/staging/media/lirc/lirc_serial.c b/drivers/staging/media/lirc/lirc_serial.c index dc79844..465796a 100644 --- a/drivers/staging/media/lirc/lirc_serial.c +++ b/drivers/staging/media/lirc/lirc_serial.c @@ -327,9 +327,6 @@ static void safe_udelay(unsigned long usecs) * time */ -/* So send_pulse can quickly convert microseconds to clocks */ -static unsigned long conv_us_to_clocks; - static int init_timing_params(unsigned int new_duty_cycle, unsigned int new_freq) { @@ -344,7 +341,6 @@ static int init_timing_params(unsigned int new_duty_cycle, /* How many clocks in a microsecond?, avoiding long long divide */ work = loops_per_sec; work *= 4295; /* 4295 = 2^32 / 1e6 */ - conv_us_to_clocks = work >> 32; /* * Carrier period in clocks, approach good up to 32GHz clock, @@ -357,10 +353,9 @@ static int init_timing_params(unsigned int new_duty_cycle, pulse_width = period * duty_cycle / 100; space_width = period - pulse_width; dprintk("in init_timing_params, freq=%d, duty_cycle=%d, " - "clk/jiffy=%ld, pulse=%ld, space=%ld, " - "conv_us_to_clocks=%ld\n", + "clk/jiffy=%ld, pulse=%ld, space=%ld\n", freq, duty_cycle, __this_cpu_read(cpu_info.loops_per_jiffy), - pulse_width, space_width, conv_us_to_clocks); + pulse_width, space_width); return 0; } #else /* ! USE_RDTSC */ @@ -431,63 +426,14 @@ static long send_pulse_irdeo(unsigned long length) return ret; } -#ifdef USE_RDTSC -/* Version that uses Pentium rdtsc instruction to measure clocks */ - -/* - * This version does sub-microsecond timing using rdtsc instruction, - * and does away with the fudged LIRC_SERIAL_TRANSMITTER_LATENCY - * Implicitly i586 architecture... - Steve - */ - -static long send_pulse_homebrew_softcarrier(unsigned long length) -{ - int flag; - unsigned long target, start, now; - - /* Get going quick as we can */ - rdtscl(start); - on(); - /* Convert length from microseconds to clocks */ - length *= conv_us_to_clocks; - /* And loop till time is up - flipping at right intervals */ - now = start; - target = pulse_width; - flag = 1; - /* - * FIXME: This looks like a hard busy wait, without even an occasional, - * polite, cpu_relax() call. There's got to be a better way? - * - * The i2c code has the result of a lot of bit-banging work, I wonder if - * there's something there which could be helpful here. - */ - while ((now - start) < length) { - /* Delay till flip time */ - do { - rdtscl(now); - } while ((now - start) < target); - - /* flip */ - if (flag) { - rdtscl(now); - off(); - target += space_width; - } else { - rdtscl(now); on(); - target += pulse_width; - } - flag = !flag; - } - rdtscl(now); - return ((now - start) - length) / conv_us_to_clocks; -} -#else /* ! USE_RDTSC */ /* Version using udelay() */ /* * here we use fixed point arithmetic, with 8 * fractional bits. that gets us within 0.1% or so of the right average * frequency, albeit with some jitter in pulse length - Steve + * + * This should use ndelay instead. */ /* To match 8 fractional bits used for pulse/space length */ @@ -520,7 +466,6 @@ static long send_pulse_homebrew_softcarrier(unsigned long length) } return (actual-length) >> 8; } -#endif /* USE_RDTSC */ static long send_pulse_homebrew(unsigned long length) { -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
