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Message-ID: <20201102101347.GN401619@phenom.ffwll.local>
Date: Mon, 2 Nov 2020 11:13:47 +0100
From: Daniel Vetter <daniel@...ll.ch>
To: Jiri Slaby <jirislaby@...nel.org>
Cc: Peilin Ye <yepeilin.cs@...il.com>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Thomas Winischhofer <thomas@...ischhofer.net>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Nicolas Pitre <nico@...xnic.net>,
"Gustavo A . R . Silva" <gustavoars@...nel.org>,
Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
George Kennedy <george.kennedy@...cle.com>,
Nathan Chancellor <natechancellor@...il.com>,
Peter Rosin <peda@...ntia.se>, linux-kernel@...r.kernel.org,
linux-usb@...r.kernel.org, dri-devel@...ts.freedesktop.org,
linux-fbdev@...r.kernel.org
Subject: Re: [PATCH v2 1/2] console: Remove dummy con_font_op() callback
implementations
On Mon, Nov 02, 2020 at 10:47:55AM +0100, Jiri Slaby wrote:
> On 02. 11. 20, 10:36, Peilin Ye wrote:
> > `struct console_font` is a UAPI structure, thus ideally should not be
> > used for kernel internal abstraction. Remove some dummy .con_font_set,
> > .con_font_default and .con_font_copy `struct consw` callback
> > implementations, to make it cleaner.
>
> ESEMANTIC_ERROR.
>
> 1) What do you refer to with the last "it"?
>
> 2) What's the purpose of mentioning struct console_font at all?
>
> 3) Could you clarify whether you checked it is safe to remove the hooks?
>
> 4) All the hooks now return ENOSYS for both consoles (and not 0). Is this
> intentional?
>
> I know answers to the first 3 questions, but you need to elaborate a bit in
> the commit log to connect those sentences. Esp. for people not dealing with
> the code on a daily basis. Ad 4) I am not sure.
Yup the behaviour change from 4) needs to be called out. I think this
should then also be done as part of the large patch series to remove the
dummy functions from all console drivers.
I don't expect the errno change to cause trouble, and it's the more honest
errno - changing fonts not supported is the truth. But if it is, we can
patch that up appropriately when we get a regression report. That's kinda
unavoidable with old crufty uapi like this one here.
Also a bikeshed: Additional information like the patch changelog or
reasons why you do something is imo best to include in the commit message
itself. It ends up looking a bit less tidy sometimes, but often there's
crucial information in these parts that was accidentally left out from the
commit message.
Thanks, Daniel
>
> > Suggested-by: Daniel Vetter <daniel@...ll.ch>
> > Signed-off-by: Peilin Ye <yepeilin.cs@...il.com>
> > ---
> > Change in v2:
> > - [v2 2/2] no longer Cc: stable, so do not Cc: stable
> >
> > Context: https://lore.kernel.org/lkml/CAKMK7uFY2zv0adjKJ_ORVFT7Zzwn075MaU0rEU7_FuqENLR=UA@mail.gmail.com/
> >
> > drivers/usb/misc/sisusbvga/sisusb_con.c | 21 ---------------------
> > drivers/video/console/dummycon.c | 20 --------------------
> > 2 files changed, 41 deletions(-)
> >
> > diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c
> > index c63e545fb105..dfa0d5ce6012 100644
> > --- a/drivers/usb/misc/sisusbvga/sisusb_con.c
> > +++ b/drivers/usb/misc/sisusbvga/sisusb_con.c
> > @@ -1345,24 +1345,6 @@ static int sisusbdummycon_blank(struct vc_data *vc, int blank, int mode_switch)
> > return 0;
> > }
> > -static int sisusbdummycon_font_set(struct vc_data *vc,
> > - struct console_font *font,
> > - unsigned int flags)
> > -{
> > - return 0;
> > -}
> > -
> > -static int sisusbdummycon_font_default(struct vc_data *vc,
> > - struct console_font *font, char *name)
> > -{
> > - return 0;
> > -}
> > -
> > -static int sisusbdummycon_font_copy(struct vc_data *vc, int con)
> > -{
> > - return 0;
> > -}
> > -
> > static const struct consw sisusb_dummy_con = {
> > .owner = THIS_MODULE,
> > .con_startup = sisusbdummycon_startup,
> > @@ -1375,9 +1357,6 @@ static const struct consw sisusb_dummy_con = {
> > .con_scroll = sisusbdummycon_scroll,
> > .con_switch = sisusbdummycon_switch,
> > .con_blank = sisusbdummycon_blank,
> > - .con_font_set = sisusbdummycon_font_set,
> > - .con_font_default = sisusbdummycon_font_default,
> > - .con_font_copy = sisusbdummycon_font_copy,
> > };
> > int
> > diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
> > index 2a0d0bda7faa..f1711b2f9ff0 100644
> > --- a/drivers/video/console/dummycon.c
> > +++ b/drivers/video/console/dummycon.c
> > @@ -124,23 +124,6 @@ static int dummycon_switch(struct vc_data *vc)
> > return 0;
> > }
> > -static int dummycon_font_set(struct vc_data *vc, struct console_font *font,
> > - unsigned int flags)
> > -{
> > - return 0;
> > -}
> > -
> > -static int dummycon_font_default(struct vc_data *vc,
> > - struct console_font *font, char *name)
> > -{
> > - return 0;
> > -}
> > -
> > -static int dummycon_font_copy(struct vc_data *vc, int con)
> > -{
> > - return 0;
> > -}
> > -
> > /*
> > * The console `switch' structure for the dummy console
> > *
> > @@ -159,8 +142,5 @@ const struct consw dummy_con = {
> > .con_scroll = dummycon_scroll,
> > .con_switch = dummycon_switch,
> > .con_blank = dummycon_blank,
> > - .con_font_set = dummycon_font_set,
> > - .con_font_default = dummycon_font_default,
> > - .con_font_copy = dummycon_font_copy,
> > };
> > EXPORT_SYMBOL_GPL(dummy_con);
> >
>
>
> --
> js
> suse labs
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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