Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
On Sun, Nov 01, 2020 at 12:32:44PM +0200, Hassan Shahbazi wrote: > On Sun, Nov 01, 2020 at 07:39:48AM +0100, Greg KH wrote: > > On Sun, Nov 01, 2020 at 02:20:10AM +0200, Hassan Shahbazi wrote: > > > Fix the checkpath.pl issue on fb_watterott.c. write_vmem and > > > write_vmem_8bit functions are within non-atomic context and can > > > safely use usleep_range. > > > see Documentation/timers/timers-howto.txt > > > > > > Signed-off-by: Hassan Shahbazi > > > --- > > > drivers/staging/fbtft/fb_watterott.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/staging/fbtft/fb_watterott.c > > > b/drivers/staging/fbtft/fb_watterott.c > > > index 76b25df376b8..afcc86a17995 100644 > > > --- a/drivers/staging/fbtft/fb_watterott.c > > > +++ b/drivers/staging/fbtft/fb_watterott.c > > > @@ -84,7 +84,7 @@ static int write_vmem(struct fbtft_par *par, size_t > > > offset, size_t len) > > > par->txbuf.buf, 10 + par->info->fix.line_length); > > > if (ret < 0) > > > return ret; > > > - udelay(300); > > > + usleep_range(300, 310); > > > } > > > > > > return 0; > > > @@ -124,7 +124,7 @@ static int write_vmem_8bit(struct fbtft_par *par, > > > size_t offset, size_t len) > > > par->txbuf.buf, 10 + par->info->var.xres); > > > if (ret < 0) > > > return ret; > > > - udelay(700); > > > + usleep_range(700, 710); > > > > How do you know that these ranges are ok? Are you able to test these > > changes with real hardware? > > > > thanks, > > > > greg k-h > > No, I don't have the hardware to test with. I just used the current > value as the minimum and added an epsilon to it for the maximum > param. It's best not to guess about this, sorry, you should have the hardware to test this type of change. thanks, greg k-h
Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
On Sun, Nov 01, 2020 at 07:39:48AM +0100, Greg KH wrote: > On Sun, Nov 01, 2020 at 02:20:10AM +0200, Hassan Shahbazi wrote: > > Fix the checkpath.pl issue on fb_watterott.c. write_vmem and > > write_vmem_8bit functions are within non-atomic context and can > > safely use usleep_range. > > see Documentation/timers/timers-howto.txt > > > > Signed-off-by: Hassan Shahbazi > > --- > > drivers/staging/fbtft/fb_watterott.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/staging/fbtft/fb_watterott.c > > b/drivers/staging/fbtft/fb_watterott.c > > index 76b25df376b8..afcc86a17995 100644 > > --- a/drivers/staging/fbtft/fb_watterott.c > > +++ b/drivers/staging/fbtft/fb_watterott.c > > @@ -84,7 +84,7 @@ static int write_vmem(struct fbtft_par *par, size_t > > offset, size_t len) > > par->txbuf.buf, 10 + par->info->fix.line_length); > > if (ret < 0) > > return ret; > > - udelay(300); > > + usleep_range(300, 310); > > } > > > > return 0; > > @@ -124,7 +124,7 @@ static int write_vmem_8bit(struct fbtft_par *par, > > size_t offset, size_t len) > > par->txbuf.buf, 10 + par->info->var.xres); > > if (ret < 0) > > return ret; > > - udelay(700); > > + usleep_range(700, 710); > > How do you know that these ranges are ok? Are you able to test these > changes with real hardware? > > thanks, > > greg k-h No, I don't have the hardware to test with. I just used the current value as the minimum and added an epsilon to it for the maximum param. best, hassan shahbazi
Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
On Sun, Nov 01, 2020 at 02:20:10AM +0200, Hassan Shahbazi wrote: > Fix the checkpath.pl issue on fb_watterott.c. write_vmem and > write_vmem_8bit functions are within non-atomic context and can > safely use usleep_range. > see Documentation/timers/timers-howto.txt > > Signed-off-by: Hassan Shahbazi > --- > drivers/staging/fbtft/fb_watterott.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/fbtft/fb_watterott.c > b/drivers/staging/fbtft/fb_watterott.c > index 76b25df376b8..afcc86a17995 100644 > --- a/drivers/staging/fbtft/fb_watterott.c > +++ b/drivers/staging/fbtft/fb_watterott.c > @@ -84,7 +84,7 @@ static int write_vmem(struct fbtft_par *par, size_t offset, > size_t len) > par->txbuf.buf, 10 + par->info->fix.line_length); > if (ret < 0) > return ret; > - udelay(300); > + usleep_range(300, 310); > } > > return 0; > @@ -124,7 +124,7 @@ static int write_vmem_8bit(struct fbtft_par *par, size_t > offset, size_t len) > par->txbuf.buf, 10 + par->info->var.xres); > if (ret < 0) > return ret; > - udelay(700); > + usleep_range(700, 710); How do you know that these ranges are ok? Are you able to test these changes with real hardware? thanks, greg k-h
[PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
Fix the checkpath.pl issue on fb_watterott.c. write_vmem and write_vmem_8bit functions are within non-atomic context and can safely use usleep_range. see Documentation/timers/timers-howto.txt Signed-off-by: Hassan Shahbazi --- drivers/staging/fbtft/fb_watterott.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/fbtft/fb_watterott.c b/drivers/staging/fbtft/fb_watterott.c index 76b25df376b8..afcc86a17995 100644 --- a/drivers/staging/fbtft/fb_watterott.c +++ b/drivers/staging/fbtft/fb_watterott.c @@ -84,7 +84,7 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len) par->txbuf.buf, 10 + par->info->fix.line_length); if (ret < 0) return ret; - udelay(300); + usleep_range(300, 310); } return 0; @@ -124,7 +124,7 @@ static int write_vmem_8bit(struct fbtft_par *par, size_t offset, size_t len) par->txbuf.buf, 10 + par->info->var.xres); if (ret < 0) return ret; - udelay(700); + usleep_range(700, 710); } return 0; -- 2.25.1
