From: Peilin Ye <yepeilin.cs@gmail.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Following up
Date: Tue, 27 Oct 2020 12:50:21 -0400 [thread overview]
Message-ID: <20201027165021.GA1178130@PWN> (raw)
In-Reply-To: <cover.1603788511.git.yepeilin.cs@gmail.com>
Hi Daniel,
More about the 3 things we've discussed before:
1. Cleaning up con_font_op():
(drivers/tty/vt/vt.c)
int con_font_op(struct vc_data *vc, struct console_font_op *op)
{
switch (op->op) {
case KD_FONT_OP_SET:
return con_font_set(vc, op);
case KD_FONT_OP_GET:
return con_font_get(vc, op);
case KD_FONT_OP_SET_DEFAULT:
return con_font_default(vc, op);
case KD_FONT_OP_COPY:
return con_font_copy(vc, op);
}
return -ENOSYS;
}
On Tue, Sep 29, 2020 at 04:38:49PM +0200, Daniel Vetter wrote:
> I think if we change the conf_font_get/set/default/copy functions to not
> take the *op struct (which is take pretty arbitrarily from one of the
> ioctl), but the parameters each needs directly, that would clean up the
> code a _lot_.
This is on my TODO list! One day I came up with some idea about
fbcon.c, so I postponed this a bit...
2. Removing dummy functions, like sisusbdummycon_font_set():
Turns out, before c396a5bf457f ("console: Expand dummy functions for
CFI"), they were just some macros:
-#define SISUSBCONDUMMY (void *)sisusbdummycon_dummy
+static int sisusbdummycon_font_set(struct vc_data *vc,
+ struct console_font *font,
+ unsigned int flags)
+{
+ return 0;
+}
...and they had been there for a very long (10+ years) time. Removing
code like this makes me a bit nervous, and...
On Tue, Sep 29, 2020 at 04:38:49PM +0200, Daniel Vetter wrote:
> This actually does something. tbh I would not be surprises if the
> fb_set utility is the only thing that uses this - with a bit of code
> search we could perhaps confirm this, and delete all the other
> implementations.
...you mentioned code search, where & what should we look at, in order
to confirm it's safe to remove them?
3. Using `font_desc` in `vc_data`:
Our plan for the gradual conversion was to use a helper function to
set font for a vc, but after reviewing the 300-ish occurrence of
`vc_font`, it seems like code doesn't usually set it as a whole:
(drivers/usb/misc/sisusbvga/sisusb_con.c)
[...]
c->vc_font.height = sisusb->current_font_height;
[...]
...that's it! It only cares about the height. There are only 4 or 5
places in fbcon.c that actually set all fields of `vc_font`, like:
vc->vc_font.width = font->width;
vc->vc_font.height = font->height;
vc->vc_font.data = (void *)(p->fontdata = font->data);
vc->vc_font.charcount = 256; /* FIXME Need to support more fonts */
To make it even more complicated, `p` is a `struct fbcon_display *`,
containing yet another font data pointer (`fontdata`) that I think
should be replaced by a `font_desc *`...
In conclusion, I think it's all about a few hard problems in fbcon.c.
I'll keep trying and see how it goes.
Thank you,
Peilin Ye
next prev parent reply other threads:[~2020-10-27 16:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 16:27 [PATCH 0/5] Preparation work for using font_desc in vc_data Peilin Ye
2020-10-27 16:31 ` [PATCH 1/5] fbdev/atafb: Remove unused extern variables Peilin Ye
2020-10-27 16:33 ` [PATCH 2/5] Fonts: Make font size unsigned in font_desc Peilin Ye
2020-10-27 16:34 ` [PATCH 3/5] Fonts: Add charcount field to font_desc Peilin Ye
2020-10-27 16:37 ` [PATCH 4/5] fbcon: Avoid hard-coding built-in font charcount Peilin Ye
2020-10-27 16:41 ` [PATCH 5/5] parisc/sticore: " Peilin Ye
2020-10-27 19:18 ` Daniel Vetter
2020-10-27 19:13 ` [PATCH 4/5] fbcon: " Daniel Vetter
2020-10-28 5:30 ` Peilin Ye
2020-10-28 15:51 ` [PATCH RFC v2 4/5] fbdev: Avoid using FNTCHARCNT() and hard-coded " Peilin Ye
2020-10-27 18:59 ` [PATCH 3/5] Fonts: Add charcount field to font_desc Daniel Vetter
2020-10-28 6:11 ` Peilin Ye
2020-10-28 6:05 ` [PATCH 3/5 v2] " Peilin Ye
2020-11-02 15:03 ` Daniel Vetter
2020-10-27 18:50 ` [PATCH 2/5] Fonts: Make font size unsigned in font_desc Daniel Vetter
2020-10-28 5:43 ` Peilin Ye
2020-10-28 8:18 ` Daniel Vetter
2020-10-28 10:30 ` Peilin Ye
2020-10-28 10:56 ` [PATCH v2 " Peilin Ye
2020-10-28 18:40 ` Daniel Vetter
2020-10-27 18:44 ` [PATCH 1/5] fbdev/atafb: Remove unused extern variables Daniel Vetter
2020-10-28 9:59 ` Geert Uytterhoeven
2020-10-28 19:25 ` Thomas Zimmermann
2020-10-27 16:50 ` Peilin Ye [this message]
2020-10-27 18:36 ` Following up Daniel Vetter
2020-10-28 5:34 ` Peilin Ye
2020-11-02 15:01 ` [PATCH 0/5] Preparation work for using font_desc in vc_data Daniel Vetter
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