* [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
@ 2020-11-01 0:20 Hassan Shahbazi
2020-11-01 6:39 ` Greg KH
0 siblings, 1 reply; 4+ messages in thread
From: Hassan Shahbazi @ 2020-11-01 0:20 UTC (permalink / raw)
To: linus.walleij
Cc: dri-devel, linux-fbdev, devel, linux-kernel, Hassan Shahbazi
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 <hassan@ninchat.com>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
2020-11-01 0:20 [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay Hassan Shahbazi
@ 2020-11-01 6:39 ` Greg KH
2020-11-01 10:32 ` Hassan Shahbazi
0 siblings, 1 reply; 4+ messages in thread
From: Greg KH @ 2020-11-01 6:39 UTC (permalink / raw)
To: Hassan Shahbazi
Cc: linus.walleij, devel, Hassan Shahbazi, linux-fbdev, linux-kernel,
dri-devel
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 <hassan@ninchat.com>
> ---
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
2020-11-01 6:39 ` Greg KH
@ 2020-11-01 10:32 ` Hassan Shahbazi
2020-11-06 10:01 ` Greg KH
0 siblings, 1 reply; 4+ messages in thread
From: Hassan Shahbazi @ 2020-11-01 10:32 UTC (permalink / raw)
To: Greg KH; +Cc: dri-devel, linux-fbdev, devel, linux-kernel
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 <hassan@ninchat.com>
> > ---
> > 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay
2020-11-01 10:32 ` Hassan Shahbazi
@ 2020-11-06 10:01 ` Greg KH
0 siblings, 0 replies; 4+ messages in thread
From: Greg KH @ 2020-11-06 10:01 UTC (permalink / raw)
To: Hassan Shahbazi; +Cc: dri-devel, linux-fbdev, devel, linux-kernel
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 <hassan@ninchat.com>
> > > ---
> > > 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
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-11-01 0:20 [PATCH] staging: fbtft: fb_watterott: fix usleep_range is preferred over udelay Hassan Shahbazi
2020-11-01 6:39 ` Greg KH
2020-11-01 10:32 ` Hassan Shahbazi
2020-11-06 10:01 ` Greg KH
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