* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 8:36 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 8:36 UTC (permalink / raw)
To: Min Guo
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > Hi greg k-h:
> > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > From: Min Guo <min.guo@mediatek.com>
> > > > >
> > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > >
> > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > but not used [-Wunused-but-set-variable]
> > > > >
> > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > ---
> > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > 1 file changed, 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > musb_channel->channel.status =
> > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > } else {
> > > > > - u8 devctl;
> > > > > -
> > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > bchannel);
> > > > > channel->actual_len = addr
> > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > < musb_channel->len) ?
> > > > > "=> reconfig 0" : "=> complete");
> > > > >
> > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > >
> > > > Are you sure that the hardware does not require this read to complete
> > > > the command? Lots of hardware is that way, so be very careful about
> > > > this. Did you test it?
> > >
> > > I have tested this patch on Mediatek's platform, and not sure if it
> > > will affect other vendors' platforms.
> > >
> > > Dear Bin:
> > >
> > > Does this patch will affect other vendors' platforms?
> >
> > The hardware specs will answer this question, what do they say about
> > this read?
>
> Sorry, I didn't seen the comment on the hardware specs indicate that
> devctl register needs to read once to take effect.
Perhaps you might want to add a comment here so that people will not
keep making this same mistake when they run auto-checkers on the
codebase?
thanks,
greg k-h
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 8:36 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 8:36 UTC (permalink / raw)
To: Min Guo
Cc: Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb, linux-kernel,
linux-arm-kernel, linux-mediatek
On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > Hi greg k-h:
> > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > From: Min Guo <min.guo@mediatek.com>
> > > > >
> > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > >
> > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > but not used [-Wunused-but-set-variable]
> > > > >
> > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > ---
> > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > 1 file changed, 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > musb_channel->channel.status =
> > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > } else {
> > > > > - u8 devctl;
> > > > > -
> > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > bchannel);
> > > > > channel->actual_len = addr
> > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > < musb_channel->len) ?
> > > > > "=> reconfig 0" : "=> complete");
> > > > >
> > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > >
> > > > Are you sure that the hardware does not require this read to complete
> > > > the command? Lots of hardware is that way, so be very careful about
> > > > this. Did you test it?
> > >
> > > I have tested this patch on Mediatek's platform, and not sure if it
> > > will affect other vendors' platforms.
> > >
> > > Dear Bin:
> > >
> > > Does this patch will affect other vendors' platforms?
> >
> > The hardware specs will answer this question, what do they say about
> > this read?
>
> Sorry, I didn't seen the comment on the hardware specs indicate that
> devctl register needs to read once to take effect.
Perhaps you might want to add a comment here so that people will not
keep making this same mistake when they run auto-checkers on the
codebase?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
2020-11-20 8:36 ` Greg Kroah-Hartman
(?)
@ 2020-11-20 9:02 ` Min Guo
-1 siblings, 0 replies; 33+ messages in thread
From: Min Guo @ 2020-11-20 9:02 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
Sorry for confused you, I searched the hardware specs, but did not find
the special description of the register devctl indicating that it needs
to be read out before the hardware can work.
> thanks,
>
> greg k-h
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 9:02 ` Min Guo
0 siblings, 0 replies; 33+ messages in thread
From: Min Guo @ 2020-11-20 9:02 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
Sorry for confused you, I searched the hardware specs, but did not find
the special description of the register devctl indicating that it needs
to be read out before the hardware can work.
> thanks,
>
> greg k-h
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 9:02 ` Min Guo
0 siblings, 0 replies; 33+ messages in thread
From: Min Guo @ 2020-11-20 9:02 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb, linux-kernel,
linux-arm-kernel, linux-mediatek
On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
Sorry for confused you, I searched the hardware specs, but did not find
the special description of the register devctl indicating that it needs
to be read out before the hardware can work.
> thanks,
>
> greg k-h
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
2020-11-20 9:02 ` Min Guo
(?)
@ 2020-11-20 9:20 ` Greg Kroah-Hartman
-1 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 9:20 UTC (permalink / raw)
To: Min Guo
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 05:02:15PM +0800, Min Guo wrote:
> On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> Sorry for confused you, I searched the hardware specs, but did not find
> the special description of the register devctl indicating that it needs
> to be read out before the hardware can work.
If this is a PCI device, that is implied as that is how all PCI devices
work, right?
What is the problem that is fixed by removing this read?
thanks,
greg k-h
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 9:20 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 9:20 UTC (permalink / raw)
To: Min Guo
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 05:02:15PM +0800, Min Guo wrote:
> On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> Sorry for confused you, I searched the hardware specs, but did not find
> the special description of the register devctl indicating that it needs
> to be read out before the hardware can work.
If this is a PCI device, that is implied as that is how all PCI devices
work, right?
What is the problem that is fixed by removing this read?
thanks,
greg k-h
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 9:20 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 9:20 UTC (permalink / raw)
To: Min Guo
Cc: Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb, linux-kernel,
linux-arm-kernel, linux-mediatek
On Fri, Nov 20, 2020 at 05:02:15PM +0800, Min Guo wrote:
> On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> Sorry for confused you, I searched the hardware specs, but did not find
> the special description of the register devctl indicating that it needs
> to be read out before the hardware can work.
If this is a PCI device, that is implied as that is how all PCI devices
work, right?
What is the problem that is fixed by removing this read?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 33+ messages in thread
* Re: [PATCH] usb: musb: remove unused variable 'devctl'
2020-11-20 8:36 ` Greg Kroah-Hartman
(?)
@ 2020-11-20 16:15 ` Alan Stern
-1 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:15 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
A better change would be
- devctl = musb_readb(mbase, MUSB_DEVCTL);
+ (void) musb_readb(mbase, MUSB_DEVCTL);
and eliminate the unused variable. Then there wouldn't be any compiler
warning.
Alan Stern
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:15 ` Alan Stern
0 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:15 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
A better change would be
- devctl = musb_readb(mbase, MUSB_DEVCTL);
+ (void) musb_readb(mbase, MUSB_DEVCTL);
and eliminate the unused variable. Then there wouldn't be any compiler
warning.
Alan Stern
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:15 ` Alan Stern
0 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:15 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Min Guo, Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb,
linux-kernel, linux-arm-kernel, linux-mediatek
On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > Hi greg k-h:
> > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > >
> > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > >
> > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > but not used [-Wunused-but-set-variable]
> > > > > >
> > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > ---
> > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > 1 file changed, 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > musb_channel->channel.status =
> > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > } else {
> > > > > > - u8 devctl;
> > > > > > -
> > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > bchannel);
> > > > > > channel->actual_len = addr
> > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > < musb_channel->len) ?
> > > > > > "=> reconfig 0" : "=> complete");
> > > > > >
> > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > >
> > > > > Are you sure that the hardware does not require this read to complete
> > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > this. Did you test it?
> > > >
> > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > will affect other vendors' platforms.
> > > >
> > > > Dear Bin:
> > > >
> > > > Does this patch will affect other vendors' platforms?
> > >
> > > The hardware specs will answer this question, what do they say about
> > > this read?
> >
> > Sorry, I didn't seen the comment on the hardware specs indicate that
> > devctl register needs to read once to take effect.
>
> Perhaps you might want to add a comment here so that people will not
> keep making this same mistake when they run auto-checkers on the
> codebase?
A better change would be
- devctl = musb_readb(mbase, MUSB_DEVCTL);
+ (void) musb_readb(mbase, MUSB_DEVCTL);
and eliminate the unused variable. Then there wouldn't be any compiler
warning.
Alan Stern
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
2020-11-20 16:15 ` Alan Stern
(?)
@ 2020-11-20 16:32 ` Greg Kroah-Hartman
-1 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 16:32 UTC (permalink / raw)
To: Alan Stern
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> A better change would be
>
> - devctl = musb_readb(mbase, MUSB_DEVCTL);
> + (void) musb_readb(mbase, MUSB_DEVCTL);
>
> and eliminate the unused variable. Then there wouldn't be any compiler
> warning.
No need for the (void), the compiler shouldn't warn about that, right?
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:32 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 16:32 UTC (permalink / raw)
To: Alan Stern
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> A better change would be
>
> - devctl = musb_readb(mbase, MUSB_DEVCTL);
> + (void) musb_readb(mbase, MUSB_DEVCTL);
>
> and eliminate the unused variable. Then there wouldn't be any compiler
> warning.
No need for the (void), the compiler shouldn't warn about that, right?
_______________________________________________
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^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:32 ` Greg Kroah-Hartman
0 siblings, 0 replies; 33+ messages in thread
From: Greg Kroah-Hartman @ 2020-11-20 16:32 UTC (permalink / raw)
To: Alan Stern
Cc: Min Guo, Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb,
linux-kernel, linux-arm-kernel, linux-mediatek
On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> On Fri, Nov 20, 2020 at 09:36:33AM +0100, Greg Kroah-Hartman wrote:
> > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote:
> > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote:
> > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote:
> > > > > Hi greg k-h:
> > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote:
> > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote:
> > > > > > > From: Min Guo <min.guo@mediatek.com>
> > > > > > >
> > > > > > > Remove unused 'devctl' variable to fix compile warnings:
> > > > > > >
> > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > > > > > > but not used [-Wunused-but-set-variable]
> > > > > > >
> > > > > > > Signed-off-by: Min Guo <min.guo@mediatek.com>
> > > > > > > ---
> > > > > > > drivers/usb/musb/musbhsdma.c | 4 ----
> > > > > > > 1 file changed, 4 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > > > > > > index 0aacfc8be5a1..7acd1635850d 100644
> > > > > > > --- a/drivers/usb/musb/musbhsdma.c
> > > > > > > +++ b/drivers/usb/musb/musbhsdma.c
> > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > musb_channel->channel.status =
> > > > > > > MUSB_DMA_STATUS_BUS_ABORT;
> > > > > > > } else {
> > > > > > > - u8 devctl;
> > > > > > > -
> > > > > > > addr = musb_read_hsdma_addr(mbase,
> > > > > > > bchannel);
> > > > > > > channel->actual_len = addr
> > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > > > > > > < musb_channel->len) ?
> > > > > > > "=> reconfig 0" : "=> complete");
> > > > > > >
> > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > > > > >
> > > > > > Are you sure that the hardware does not require this read to complete
> > > > > > the command? Lots of hardware is that way, so be very careful about
> > > > > > this. Did you test it?
> > > > >
> > > > > I have tested this patch on Mediatek's platform, and not sure if it
> > > > > will affect other vendors' platforms.
> > > > >
> > > > > Dear Bin:
> > > > >
> > > > > Does this patch will affect other vendors' platforms?
> > > >
> > > > The hardware specs will answer this question, what do they say about
> > > > this read?
> > >
> > > Sorry, I didn't seen the comment on the hardware specs indicate that
> > > devctl register needs to read once to take effect.
> >
> > Perhaps you might want to add a comment here so that people will not
> > keep making this same mistake when they run auto-checkers on the
> > codebase?
>
> A better change would be
>
> - devctl = musb_readb(mbase, MUSB_DEVCTL);
> + (void) musb_readb(mbase, MUSB_DEVCTL);
>
> and eliminate the unused variable. Then there wouldn't be any compiler
> warning.
No need for the (void), the compiler shouldn't warn about that, right?
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH] usb: musb: remove unused variable 'devctl'
2020-11-20 16:32 ` Greg Kroah-Hartman
(?)
@ 2020-11-20 16:37 ` Alan Stern
-1 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:37 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 05:32:44PM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> > > Perhaps you might want to add a comment here so that people will not
> > > keep making this same mistake when they run auto-checkers on the
> > > codebase?
> >
> > A better change would be
> >
> > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > + (void) musb_readb(mbase, MUSB_DEVCTL);
> >
> > and eliminate the unused variable. Then there wouldn't be any compiler
> > warning.
>
> No need for the (void), the compiler shouldn't warn about that, right?
True, but it clearly indicates to a human reader that the value was
intended to be read and thrown away. Alternatively, the (void) cast
could be left out and a comment added.
Alan Stern
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
^ permalink raw reply [flat|nested] 33+ messages in thread
* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:37 ` Alan Stern
0 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:37 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-usb, linux-kernel, chunfeng.yun, linux-mediatek, Min Guo,
Matthias Brugger, Bin Liu, linux-arm-kernel
On Fri, Nov 20, 2020 at 05:32:44PM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> > > Perhaps you might want to add a comment here so that people will not
> > > keep making this same mistake when they run auto-checkers on the
> > > codebase?
> >
> > A better change would be
> >
> > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > + (void) musb_readb(mbase, MUSB_DEVCTL);
> >
> > and eliminate the unused variable. Then there wouldn't be any compiler
> > warning.
>
> No need for the (void), the compiler shouldn't warn about that, right?
True, but it clearly indicates to a human reader that the value was
intended to be read and thrown away. Alternatively, the (void) cast
could be left out and a comment added.
Alan Stern
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 33+ messages in thread
* Re: [PATCH] usb: musb: remove unused variable 'devctl'
@ 2020-11-20 16:37 ` Alan Stern
0 siblings, 0 replies; 33+ messages in thread
From: Alan Stern @ 2020-11-20 16:37 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Min Guo, Bin Liu, Matthias Brugger, chunfeng.yun, linux-usb,
linux-kernel, linux-arm-kernel, linux-mediatek
On Fri, Nov 20, 2020 at 05:32:44PM +0100, Greg Kroah-Hartman wrote:
> On Fri, Nov 20, 2020 at 11:15:19AM -0500, Alan Stern wrote:
> > > Perhaps you might want to add a comment here so that people will not
> > > keep making this same mistake when they run auto-checkers on the
> > > codebase?
> >
> > A better change would be
> >
> > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > + (void) musb_readb(mbase, MUSB_DEVCTL);
> >
> > and eliminate the unused variable. Then there wouldn't be any compiler
> > warning.
>
> No need for the (void), the compiler shouldn't warn about that, right?
True, but it clearly indicates to a human reader that the value was
intended to be read and thrown away. Alternatively, the (void) cast
could be left out and a comment added.
Alan Stern
^ permalink raw reply [flat|nested] 33+ messages in thread