Re: [PATCH v4 7/7] drm/log: Add integer scaling support

[Jocelyn Falempe <jfalempe@xxxxxxxxxx>]

On 11/10/2024 13:18, Jani Nikula wrote:
> On Fri, 11 Oct 2024, Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote:
> > Add a module parameter, to increase the font size for HiDPI screen.
> > Even with CONFIG_FONT_TER16x32, it can still be a bit small to read.
> > In this case, adding drm_log.scale=2 to your kernel command line will
> > double the character size.
> >
> > Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/drm_log.c | 27 ++++++++++++++++++---------
> >   1 file changed, 18 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_log.c b/drivers/gpu/drm/drm_log.c
> > index 07d151300146..e44c10819bd0 100644
> > --- a/drivers/gpu/drm/drm_log.c
> > +++ b/drivers/gpu/drm/drm_log.c
> > @@ -25,6 +25,10 @@ MODULE_AUTHOR("Jocelyn Falempe");
> >   MODULE_DESCRIPTION("DRM boot logger");
> >   MODULE_LICENSE("GPL");
> >   
> > +static uint scale = 1;
>
> Drive-by nit, please use regular types instead of sysv "uint".

ok, you're right. It looks like the most common pattern is to use 
unsigned int for the variable but still call module_param() with uint.
I will fix that for v5.

Thanks,

--

Jocelyn
> BR,
> Jani.
>
> > +module_param(scale, uint, 0444);
> > +MODULE_PARM_DESC(scale, "Integer scaling factor for drm_log, default is 1");
> > +
> >   /**
> >    * DOC: overview
> >    *
> > @@ -38,6 +42,8 @@ struct drm_log_scanout {
> >   	const struct font_desc *font;
> >   	u32 rows;
> >   	u32 columns;
> > +	u32 scaled_font_h;
> > +	u32 scaled_font_w;
> >   	u32 line;
> >   	u32 format;
> >   	u32 px_width;
> > @@ -67,7 +73,7 @@ static struct drm_log *console_to_drm_log(struct console *con)
> >   
> >   static void drm_log_blit(struct iosys_map *dst, unsigned int dst_pitch,
> >   			 const u8 *src, unsigned int src_pitch,
> > -			 u32 height, u32 width, u32 scale, u32 px_width, u32 color)
> > +			 u32 height, u32 width, u32 px_width, u32 color)
> >   {
> >   	switch (px_width) {
> >   	case 2:
> > @@ -87,7 +93,7 @@ static void drm_log_blit(struct iosys_map *dst, unsigned int dst_pitch,
> >   static void drm_log_clear_line(struct drm_log_scanout *scanout, u32 line)
> >   {
> >   	struct drm_framebuffer *fb = scanout->buffer->fb;
> > -	unsigned long height = scanout->font->height;
> > +	unsigned long height = scanout->scaled_font_h;
> >   	struct iosys_map map;
> >   	struct drm_rect r = DRM_RECT_INIT(0, line * height, fb->width, height);
> >   
> > @@ -107,8 +113,8 @@ static void drm_log_draw_line(struct drm_log_scanout *scanout, const char *s,
> >   	size_t font_pitch = DIV_ROUND_UP(font->width, 8);
> >   	const u8 *src;
> >   	u32 px_width = fb->format->cpp[0];
> > -	struct drm_rect r = DRM_RECT_INIT(0, scanout->line * font->height,
> > -					  fb->width, (scanout->line + 1) * font->height);
> > +	struct drm_rect r = DRM_RECT_INIT(0, scanout->line * scanout->scaled_font_h,
> > +					  fb->width, (scanout->line + 1) * scanout->scaled_font_h);
> >   	u32 i;
> >   
> >   	if (drm_client_buffer_vmap_local(scanout->buffer, &map))
> > @@ -118,9 +124,10 @@ static void drm_log_draw_line(struct drm_log_scanout *scanout, const char *s,
> >   	for (i = 0; i < len && i < scanout->columns; i++) {
> >   		u32 color = (i < prefix_len) ? scanout->prefix_color : scanout->front_color;
> >   		src = drm_draw_get_char_bitmap(font, s[i], font_pitch);
> > -		drm_log_blit(&map, fb->pitches[0], src, font_pitch, font->height, font->width,
> > -			     1, px_width, color);
> > -		iosys_map_incr(&map, font->width * px_width);
> > +		drm_log_blit(&map, fb->pitches[0], src, font_pitch,
> > +			     scanout->scaled_font_h, scanout->scaled_font_w,
> > +			     px_width, color);
> > +		iosys_map_incr(&map, scanout->scaled_font_w * px_width);
> >   	}
> >   
> >   	scanout->line++;
> > @@ -205,8 +212,10 @@ static int drm_log_setup_modeset(struct drm_client_dev *client,
> >   		return -ENOMEM;
> >   	}
> >   	mode_set->fb = scanout->buffer->fb;
> > -	scanout->rows = height / scanout->font->height;
> > -	scanout->columns = width / scanout->font->width;
> > +	scanout->scaled_font_h = scanout->font->height * scale;
> > +	scanout->scaled_font_w = scanout->font->width * scale;
> > +	scanout->rows = height / scanout->scaled_font_h;
> > +	scanout->columns = width / scanout->scaled_font_w;
> >   	scanout->front_color = drm_draw_color_from_xrgb8888(0xffffff, format);
> >   	scanout->prefix_color = drm_draw_color_from_xrgb8888(0x4e9a06, format);
> >   	return 0;