Re: [PATCH] gpu:drm:Change calls to mdelay to msleep in the functions,send_pkg_prepare and send_pkg_done for the file,mdfld_dsi_pkg_sender.c

Re: [PATCH] gpu:drm:Change calls to mdelay to msleep in the functions,send_pkg_prepare and send_pkg_done for the file,mdfld_dsi_pkg_sender.c

[Alan Cox]

On Sat, 2015-01-10 at 23:31 -0500, Nicholas Krause wrote:
> Changes various calls in the functions,send_pkg_prepare and send_pkg_done
> for mdelay to msleep. These changes are needed due to use working with
> various sleep modes supported by this hardware and thus needing to sleep
> for a small duration instead of using the respectful delay function due
> to the need to sleep rather then busy loop the CPU(s) and waste CPU cycles
> on the system that could be used to handle other tasks.
> 
> Signed-off-by: Nicholas Krause <xerofoify@gmail.com>

NAK

Like every other TODO you've been mucking with at random this one is
there for a reason.

We can't sleep at this point.

Re: [PATCH] gpu:drm:Change calls to mdelay to msleep in the functions,send_pkg_prepare and send_pkg_done for the file,mdfld_dsi_pkg_sender.c

[Thierry Reding]

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On Mon, Jan 12, 2015 at 01:29:27PM +0000, Alan Cox wrote:
> On Sat, 2015-01-10 at 23:31 -0500, Nicholas Krause wrote:
> > Changes various calls in the functions,send_pkg_prepare and send_pkg_done
> > for mdelay to msleep. These changes are needed due to use working with
> > various sleep modes supported by this hardware and thus needing to sleep
> > for a small duration instead of using the respectful delay function due
> > to the need to sleep rather then busy loop the CPU(s) and waste CPU cycles
> > on the system that could be used to handle other tasks.
> > 
> > Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> 
> NAK
> 
> Like every other TODO you've been mucking with at random this one is
> there for a reason.
> 
> We can't sleep at this point.

From a quick look it seems like the only reason why we can't sleep is
because sender->lock is a spinlock. But it would seem that it could
simply be a mutex, in which case the delays could become sleeps.

Do you happen to remember if there were specific reasons to make this a
spinlock rather than a mutex?

Thierry

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Re: [PATCH] gpu:drm:Change calls to mdelay to msleep in the functions,send_pkg_prepare and send_pkg_done for the file,mdfld_dsi_pkg_sender.c

[Alan Cox]

On Mon, 2015-01-12 at 17:12 +0100, Thierry Reding wrote:
> On Mon, Jan 12, 2015 at 01:29:27PM +0000, Alan Cox wrote:
> > On Sat, 2015-01-10 at 23:31 -0500, Nicholas Krause wrote:
> > > Changes various calls in the functions,send_pkg_prepare and send_pkg_done
> > > for mdelay to msleep. These changes are needed due to use working with
> > > various sleep modes supported by this hardware and thus needing to sleep
> > > for a small duration instead of using the respectful delay function due
> > > to the need to sleep rather then busy loop the CPU(s) and waste CPU cycles
> > > on the system that could be used to handle other tasks.
> > > 
> > > Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> > 
> > NAK
> > 
> > Like every other TODO you've been mucking with at random this one is
> > there for a reason.
> > 
> > We can't sleep at this point.
> 
> From a quick look it seems like the only reason why we can't sleep is
> because sender->lock is a spinlock. But it would seem that it could
> simply be a mutex, in which case the delays could become sleeps.
> 
> Do you happen to remember if there were specific reasons to make this a
> spinlock rather than a mutex?

I don't remember the full details and since I don't currently have a
test platform for it, and its obsolete I don't want to touch it.

If someone else does fine, but they need to verify it on real hardware.

Alan