From: Niklas Schnelle <schnelle@linux.ibm.com>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Geert Uytterhoeven" <geert@linux-m68k.org>
Cc: linux-arch@vger.kernel.org, "Arnd Bergmann" <arnd@kernel.org>,
linux-fbdev@vger.kernel.org, "Albert Ou" <aou@eecs.berkeley.edu>,
"Arnd Bergmann" <arnd@arndb.de>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Helge Deller" <deller@gmx.de>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org,
"Alan Stern" <stern@rowland.harvard.edu>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>
Subject: Re: [PATCH v3 35/38] video: handle HAS_IOPORT dependencies
Date: Thu, 23 Mar 2023 15:17:38 +0100 [thread overview]
Message-ID: <917b95c9af1b80843b8a361d1b7fa337a25105e7.camel@linux.ibm.com> (raw)
In-Reply-To: <ZBGbxDWEhqr8hhgU@intel.com>
On Wed, 2023-03-15 at 12:19 +0200, Ville Syrjälä wrote:
> On Wed, Mar 15, 2023 at 09:16:50AM +0100, Geert Uytterhoeven wrote:
> > Hi Niklas,
> >
> > On Tue, Mar 14, 2023 at 1:13 PM Niklas Schnelle <schnelle@linux.ibm.com> wrote:
> > > In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> > > not being declared. We thus need to add HAS_IOPORT as dependency for
> > > those drivers using them and guard inline code in headers.
> > >
> > > Co-developed-by: Arnd Bergmann <arnd@kernel.org>
> > > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/video/fbdev/Kconfig
> > > +++ b/drivers/video/fbdev/Kconfig
> >
> > > @@ -1284,7 +1285,7 @@ config FB_ATY128_BACKLIGHT
> > >
> > > config FB_ATY
> > > tristate "ATI Mach64 display support" if PCI || ATARI
> > > - depends on FB && !SPARC32
> > > + depends on FB && HAS_IOPORT && !SPARC32
> >
> > On Atari, this works without ATARI_ROM_ISA, hence it must not depend
> > on HAS_IOPORT.
> > The only call to inb() is inside a section protected by #ifdef
> > CONFIG_PCI. So:
>
> That piece of code is a nop anyway. We immediately overwrite
> clk_wr_offset with a hardcoded selection after the register reads.
> So if you nuke that nop code then no IOPORT dependency required
> at all.
>
I agree this "looks" like a nop but are we sure the inb() doesn't have
side effects?
(for reference drivers/video/fbdev/aty/aty/atyfb_base.c:
atyfb_setup_generc() towards the end)
It does feel a bit out of scope for this series but if it's really a
nop nuking it surely is the cleaner solution.
Thanks,
Niklas
WARNING: multiple messages have this Message-ID (diff)
From: Niklas Schnelle <schnelle@linux.ibm.com>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Geert Uytterhoeven" <geert@linux-m68k.org>
Cc: linux-arch@vger.kernel.org, "Arnd Bergmann" <arnd@kernel.org>,
linux-fbdev@vger.kernel.org, "Albert Ou" <aou@eecs.berkeley.edu>,
"Arnd Bergmann" <arnd@arndb.de>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Helge Deller" <deller@gmx.de>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org,
"Alan Stern" <stern@rowland.harvard.edu>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>
Subject: Re: [PATCH v3 35/38] video: handle HAS_IOPORT dependencies
Date: Thu, 23 Mar 2023 15:17:38 +0100 [thread overview]
Message-ID: <917b95c9af1b80843b8a361d1b7fa337a25105e7.camel@linux.ibm.com> (raw)
In-Reply-To: <ZBGbxDWEhqr8hhgU@intel.com>
On Wed, 2023-03-15 at 12:19 +0200, Ville Syrjälä wrote:
> On Wed, Mar 15, 2023 at 09:16:50AM +0100, Geert Uytterhoeven wrote:
> > Hi Niklas,
> >
> > On Tue, Mar 14, 2023 at 1:13 PM Niklas Schnelle <schnelle@linux.ibm.com> wrote:
> > > In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> > > not being declared. We thus need to add HAS_IOPORT as dependency for
> > > those drivers using them and guard inline code in headers.
> > >
> > > Co-developed-by: Arnd Bergmann <arnd@kernel.org>
> > > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/video/fbdev/Kconfig
> > > +++ b/drivers/video/fbdev/Kconfig
> >
> > > @@ -1284,7 +1285,7 @@ config FB_ATY128_BACKLIGHT
> > >
> > > config FB_ATY
> > > tristate "ATI Mach64 display support" if PCI || ATARI
> > > - depends on FB && !SPARC32
> > > + depends on FB && HAS_IOPORT && !SPARC32
> >
> > On Atari, this works without ATARI_ROM_ISA, hence it must not depend
> > on HAS_IOPORT.
> > The only call to inb() is inside a section protected by #ifdef
> > CONFIG_PCI. So:
>
> That piece of code is a nop anyway. We immediately overwrite
> clk_wr_offset with a hardcoded selection after the register reads.
> So if you nuke that nop code then no IOPORT dependency required
> at all.
>
I agree this "looks" like a nop but are we sure the inb() doesn't have
side effects?
(for reference drivers/video/fbdev/aty/aty/atyfb_base.c:
atyfb_setup_generc() towards the end)
It does feel a bit out of scope for this series but if it's really a
nop nuking it surely is the cleaner solution.
Thanks,
Niklas
next prev parent reply other threads:[~2023-03-23 14:18 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-14 12:11 [PATCH v3 00/38] Kconfig: Introduce HAS_IOPORT config option Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 01/38] Kconfig: introduce HAS_IOPORT option and select it as necessary Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-14 12:37 ` Johannes Berg
2023-03-14 12:37 ` Johannes Berg
2023-03-14 12:37 ` Johannes Berg
2023-03-14 12:37 ` Johannes Berg
2023-03-14 12:37 ` Johannes Berg
2023-03-14 12:37 ` Johannes Berg
2023-03-23 13:23 ` Niklas Schnelle
2023-03-23 13:23 ` Niklas Schnelle
2023-03-23 13:23 ` Niklas Schnelle
2023-03-23 13:23 ` Niklas Schnelle
2023-03-23 13:23 ` Niklas Schnelle
2023-03-23 13:23 ` Niklas Schnelle
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 12:48 ` Geert Uytterhoeven
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 13:29 ` Arnd Bergmann
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:11 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 16:37 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 02/38] ata: add HAS_IOPORT dependencies Niklas Schnelle
2023-03-15 1:23 ` Damien Le Moal
2023-03-15 6:46 ` Arnd Bergmann
2023-03-15 7:15 ` Damien Le Moal
2023-03-15 7:15 ` Damien Le Moal
2023-03-15 8:39 ` Geert Uytterhoeven
2023-03-15 9:12 ` Damien Le Moal
2023-03-15 11:36 ` Geert Uytterhoeven
2023-03-15 23:57 ` Damien Le Moal
2023-03-16 15:21 ` Arnd Bergmann
2023-04-28 13:32 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 03/38] char: impi, tpm: depend on HAS_IOPORT Niklas Schnelle
2023-03-14 12:20 ` Jarkko Sakkinen
2023-03-14 14:01 ` Arnd Bergmann
2023-03-14 13:52 ` Corey Minyard
2023-03-14 14:17 ` Geert Uytterhoeven
2023-03-14 15:08 ` Arnd Bergmann
2023-03-21 14:33 ` Jason Gunthorpe
2023-03-14 12:11 ` [PATCH v3 04/38] comedi: add HAS_IOPORT dependencies Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 05/38] counter: " Niklas Schnelle
2023-03-14 12:41 ` William Breathitt Gray
2023-04-28 13:27 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 06/38] /dev/port: don't compile file operations without CONFIG_DEVPORT Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 07/38] drm: handle HAS_IOPORT dependencies Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-15 11:54 ` Jani Nikula
2023-03-15 11:54 ` Jani Nikula
2023-03-15 11:54 ` Jani Nikula
2023-03-23 15:05 ` Niklas Schnelle
2023-03-23 15:05 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 08/38] firmware: dmi-sysfs: handle HAS_IOPORT=n Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 09/38] gpio: add HAS_IOPORT dependencies Niklas Schnelle
2023-03-15 8:42 ` Linus Walleij
2023-04-28 14:41 ` Niklas Schnelle
2023-05-01 12:29 ` Linus Walleij
2023-03-14 12:11 ` [PATCH v3 10/38] hwmon: " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 11/38] i2c: " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 12/38] iio: ad7606: Kconfig: " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 13/38] Input: " Niklas Schnelle
2023-03-15 8:22 ` Geert Uytterhoeven
2023-04-28 14:50 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 14/38] Input: gameport: add ISA and " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 15/38] leds: add " Niklas Schnelle
2023-03-16 16:14 ` Lee Jones
2023-03-23 12:42 ` Niklas Schnelle
2023-03-23 13:32 ` Arnd Bergmann
2023-03-23 14:02 ` Niklas Schnelle
2023-03-23 14:05 ` Arnd Bergmann
2023-03-23 16:11 ` Geert Uytterhoeven
2023-03-23 16:25 ` Arnd Bergmann
2023-03-23 14:53 ` Lee Jones
2023-03-23 15:33 ` Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 16/38] media: " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 17/38] misc: " Niklas Schnelle
2023-03-14 12:11 ` [PATCH v3 18/38] mISDN: " Niklas Schnelle
2023-03-15 5:41 ` Jakub Kicinski
2023-03-14 12:11 ` [PATCH v3 19/38] mpt fusion: " Niklas Schnelle
2023-03-14 12:11 ` [Intel-wired-lan] [PATCH v3 20/38] net: handle " Niklas Schnelle
2023-03-14 12:11 ` Niklas Schnelle
2023-03-15 5:41 ` Jakub Kicinski
2023-03-15 5:41 ` Jakub Kicinski
2023-03-15 5:41 ` [Intel-wired-lan] " Jakub Kicinski
2023-03-15 9:47 ` Maciej W. Rozycki
2023-03-15 9:47 ` Maciej W. Rozycki
2023-03-14 12:11 ` [PATCH v3 21/38] parport: PC style parport depends on HAS_IOPORT Niklas Schnelle
2023-03-14 14:12 ` Arnd Bergmann
2023-05-02 13:40 ` Niklas Schnelle
2023-05-02 15:30 ` Bjorn Helgaas
2023-03-14 12:12 ` [PATCH v3 22/38] PCI: Make quirk using inw() depend " Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 23/38] PCI/sysfs: Make I/O resource " Niklas Schnelle
2023-03-14 16:05 ` Bjorn Helgaas
2023-03-14 12:12 ` [PATCH v3 24/38] pcmcia: add HAS_IOPORT dependencies Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 25/38] platform: " Niklas Schnelle
2023-03-15 2:21 ` Tzung-Bi Shih
2023-03-14 12:12 ` [PATCH v3 26/38] pnp: " Niklas Schnelle
2023-03-20 17:37 ` Rafael J. Wysocki
2023-03-21 13:56 ` Rafael J. Wysocki
2023-03-23 12:55 ` Niklas Schnelle
2023-03-24 18:45 ` Wysocki, Rafael J
2023-03-14 12:12 ` [PATCH v3 27/38] power: " Niklas Schnelle
2023-03-29 23:01 ` Sebastian Reichel
2023-03-14 12:12 ` [PATCH v3 28/38] rtc: " Niklas Schnelle
2023-03-14 12:52 ` Alexandre Belloni
2023-05-08 15:36 ` Niklas Schnelle
2023-05-08 20:01 ` Arnd Bergmann
2023-05-09 6:38 ` Geert Uytterhoeven
2023-05-09 8:22 ` Arnd Bergmann
2023-05-09 8:51 ` Geert Uytterhoeven
2023-05-09 9:46 ` Arnd Bergmann
2023-03-14 12:12 ` [PATCH v3 29/38] scsi: " Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 30/38] sound: " Niklas Schnelle
2023-03-14 12:33 ` Takashi Iwai
2023-03-14 12:33 ` Takashi Iwai
2023-05-08 16:41 ` Niklas Schnelle
2023-05-08 16:41 ` Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 31/38] speakup: add HAS_IOPORT dependency for SPEAKUP_SERIALIO Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 32/38] staging: add HAS_IOPORT dependencies Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 33/38] tty: serial: handle " Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 34/38] usb: " Niklas Schnelle
2023-03-14 14:56 ` Arnd Bergmann
2023-03-14 12:12 ` [PATCH v3 35/38] video: " Niklas Schnelle
2023-03-14 12:12 ` Niklas Schnelle
2023-03-15 8:16 ` Geert Uytterhoeven
2023-03-15 8:16 ` Geert Uytterhoeven
2023-03-15 10:19 ` Ville Syrjälä
2023-03-15 10:19 ` Ville Syrjälä
2023-03-23 14:17 ` Niklas Schnelle [this message]
2023-03-23 14:17 ` Niklas Schnelle
2023-03-23 16:08 ` Ville Syrjälä
2023-03-23 16:08 ` Ville Syrjälä
2023-05-08 17:09 ` Niklas Schnelle
2023-05-08 17:09 ` Niklas Schnelle
2023-03-14 12:12 ` [PATCH v3 36/38] watchdog: add " Niklas Schnelle
2023-03-14 14:21 ` Guenter Roeck
2023-03-14 12:12 ` [PATCH v3 37/38] wireless: " Niklas Schnelle
2023-03-15 5:26 ` Kalle Valo
2023-03-14 12:12 ` [PATCH v3 38/38] asm-generic/io.h: drop inb() etc for HAS_IOPORT=n Niklas Schnelle
2023-03-14 14:05 ` [PATCH v3 00/38] Kconfig: Introduce HAS_IOPORT config option Arnd Bergmann
2023-03-14 14:05 ` Arnd Bergmann
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