Messages in this thread Patch in this message | | | From | Nicholas Mc Guire <> | Subject | [PATCH V2] staging: wilc1000: give usleep_range a range | Date | Thu, 11 Apr 2019 05:31:21 +0200 |
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From: Nicholas Mc Guire <hofrat@osadl.org>
usleep_range() is called in non-atomic context so there is little point in setting min==max as the jitter of hrtimer is determined by interruptions anyway. usleep_range can only perform the intended coalescence if some room for placing the hrtimer is provided. Given the range of milliseconds the delay will be 2+ anyway - so make it 2-2.5 ms which gives hrtimers space to optimize without negatively impacting performance.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> ---
Problem located with an experimental coccinelle script ./drivers/staging/wilc1000/wilc_wlan.c:411:4-16: WARNING: inefficient usleep_range with range 0 (min==max) ./drivers/staging/wilc1000/wilc_wlan.c:426:4-16: WARNING: inefficient usleep_range with range 0 (min==max)
V2: Based on feedback from Adham Abozaeid <Adham.Abozaeid@microchip.com> that since this is in the transmit path 5ms could impact throughput but adding 500 microseconds should be tolerable.
Patch was compile tested with: x86_64_defconfig + Staging=y, WILC1000_SDIO=m, WILC1000_SPI=m, WILC1000=m
Patch is against 5.1-rc4 (localversion-next is -next-20190410)
drivers/staging/wilc1000/wilc_wlan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/wilc1000/wilc_wlan.c b/drivers/staging/wilc1000/wilc_wlan.c index c238969..42da533 100644 --- a/drivers/staging/wilc1000/wilc_wlan.c +++ b/drivers/staging/wilc1000/wilc_wlan.c @@ -408,7 +408,7 @@ void chip_wakeup(struct wilc *wilc) wilc->hif_func->hif_write_reg(wilc, 1, reg & ~BIT(1)); do { - usleep_range(2 * 1000, 2 * 1000); + usleep_range(2000, 2500); wilc_get_chipid(wilc, true); } while (wilc_get_chipid(wilc, true) == 0); } while (wilc_get_chipid(wilc, true) == 0); @@ -423,7 +423,7 @@ void chip_wakeup(struct wilc *wilc) &clk_status_reg); while ((clk_status_reg & 0x1) == 0) { - usleep_range(2 * 1000, 2 * 1000); + usleep_range(2000, 2500); wilc->hif_func->hif_read_reg(wilc, 0xf1, &clk_status_reg); -- 2.1.4
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