[PATCH 0/4] fbdev: Remove global screen_info in efifb/vesafb

[PATCH 0/4] fbdev: Remove global screen_info in efifb/vesafb

[Thomas Zimmermann]

Replace the global instance of screen_info with the per-device instance
that is set by the sysfb code. The use of the global screen_info should
be limited and ideally be pushed into per-architecture code.

Thomas Zimmermann (4):
  fbdev/efifb: Replace references to global screen_info by local pointer
  fbdev/efifb: Use screen_info pointer from device
  fbdev/vesafb: Replace references to global screen_info by local
    pointer
  fbdev/vesafb: Use screen_info pointer from device

 drivers/video/fbdev/efifb.c  | 120 +++++++++++++++++++----------------
 drivers/video/fbdev/vesafb.c |  73 ++++++++++++---------
 2 files changed, 107 insertions(+), 86 deletions(-)

-- 
2.43.0

[PATCH 1/4] fbdev/efifb: Replace references to global screen_info by local pointer

[Thomas Zimmermann]

Get the global screen_info's address once and access the data via
this pointer. Limits the use of global state.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/efifb.c | 113 ++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 55 deletions(-)

diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index f9b4ddd592ce4..6cbb65bbe1110 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -147,10 +147,9 @@ static bool efifb_bgrt_sanity_check(struct screen_info *si, u32 bmp_width)
 }
 #endif
 
-static void efifb_show_boot_graphics(struct fb_info *info)
+static void efifb_show_boot_graphics(struct fb_info *info, struct screen_info *si)
 {
 	u32 bmp_width, bmp_height, bmp_pitch, dst_x, y, src_y;
-	struct screen_info *si = &screen_info;
 	struct bmp_file_header *file_header;
 	struct bmp_dib_header *dib_header;
 	void *bgrt_image = NULL;
@@ -282,7 +281,7 @@ static const struct fb_ops efifb_ops = {
 	.fb_setcolreg	= efifb_setcolreg,
 };
 
-static int efifb_setup(char *options)
+static int efifb_setup(struct screen_info *si, char *options)
 {
 	char *this_opt;
 
@@ -290,16 +289,16 @@ static int efifb_setup(char *options)
 		while ((this_opt = strsep(&options, ",")) != NULL) {
 			if (!*this_opt) continue;
 
-			efifb_setup_from_dmi(&screen_info, this_opt);
+			efifb_setup_from_dmi(si, this_opt);
 
 			if (!strncmp(this_opt, "base:", 5))
-				screen_info.lfb_base = simple_strtoul(this_opt+5, NULL, 0);
+				si->lfb_base = simple_strtoul(this_opt+5, NULL, 0);
 			else if (!strncmp(this_opt, "stride:", 7))
-				screen_info.lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
+				si->lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
 			else if (!strncmp(this_opt, "height:", 7))
-				screen_info.lfb_height = simple_strtoul(this_opt+7, NULL, 0);
+				si->lfb_height = simple_strtoul(this_opt+7, NULL, 0);
 			else if (!strncmp(this_opt, "width:", 6))
-				screen_info.lfb_width = simple_strtoul(this_opt+6, NULL, 0);
+				si->lfb_width = simple_strtoul(this_opt+6, NULL, 0);
 			else if (!strcmp(this_opt, "nowc"))
 				mem_flags &= ~EFI_MEMORY_WC;
 			else if (!strcmp(this_opt, "nobgrt"))
@@ -310,15 +309,15 @@ static int efifb_setup(char *options)
 	return 0;
 }
 
-static inline bool fb_base_is_valid(void)
+static inline bool fb_base_is_valid(struct screen_info *si)
 {
-	if (screen_info.lfb_base)
+	if (si->lfb_base)
 		return true;
 
-	if (!(screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE))
+	if (!(si->capabilities & VIDEO_CAPABILITY_64BIT_BASE))
 		return false;
 
-	if (screen_info.ext_lfb_base)
+	if (si->ext_lfb_base)
 		return true;
 
 	return false;
@@ -329,7 +328,10 @@ static ssize_t name##_show(struct device *dev,				\
 			   struct device_attribute *attr,		\
 			   char *buf)					\
 {									\
-	return sprintf(buf, fmt "\n", (screen_info.lfb_##name));	\
+	struct screen_info *si = dev_get_platdata(dev);			\
+	if (!si)							\
+		return -ENODEV;						\
+	return sprintf(buf, fmt "\n", (si->lfb_##name));		\
 }									\
 static DEVICE_ATTR_RO(name)
 
@@ -356,6 +358,7 @@ static u64 bar_offset;
 
 static int efifb_probe(struct platform_device *dev)
 {
+	struct screen_info *si = &screen_info;
 	struct fb_info *info;
 	struct efifb_par *par;
 	int err, orientation;
@@ -365,48 +368,48 @@ static int efifb_probe(struct platform_device *dev)
 	char *option = NULL;
 	efi_memory_desc_t md;
 
-	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
+	if (si->orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
 		return -ENODEV;
 
 	if (fb_get_options("efifb", &option))
 		return -ENODEV;
-	efifb_setup(option);
+	efifb_setup(si, option);
 
 	/* We don't get linelength from UGA Draw Protocol, only from
 	 * EFI Graphics Protocol.  So if it's not in DMI, and it's not
 	 * passed in from the user, we really can't use the framebuffer.
 	 */
-	if (!screen_info.lfb_linelength)
+	if (!si->lfb_linelength)
 		return -ENODEV;
 
-	if (!screen_info.lfb_depth)
-		screen_info.lfb_depth = 32;
-	if (!screen_info.pages)
-		screen_info.pages = 1;
-	if (!fb_base_is_valid()) {
+	if (!si->lfb_depth)
+		si->lfb_depth = 32;
+	if (!si->pages)
+		si->pages = 1;
+	if (!fb_base_is_valid(si)) {
 		printk(KERN_DEBUG "efifb: invalid framebuffer address\n");
 		return -ENODEV;
 	}
 	printk(KERN_INFO "efifb: probing for efifb\n");
 
 	/* just assume they're all unset if any are */
-	if (!screen_info.blue_size) {
-		screen_info.blue_size = 8;
-		screen_info.blue_pos = 0;
-		screen_info.green_size = 8;
-		screen_info.green_pos = 8;
-		screen_info.red_size = 8;
-		screen_info.red_pos = 16;
-		screen_info.rsvd_size = 8;
-		screen_info.rsvd_pos = 24;
+	if (!si->blue_size) {
+		si->blue_size = 8;
+		si->blue_pos = 0;
+		si->green_size = 8;
+		si->green_pos = 8;
+		si->red_size = 8;
+		si->red_pos = 16;
+		si->rsvd_size = 8;
+		si->rsvd_pos = 24;
 	}
 
-	efifb_fix.smem_start = screen_info.lfb_base;
+	efifb_fix.smem_start = si->lfb_base;
 
-	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
+	if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
 		u64 ext_lfb_base;
 
-		ext_lfb_base = (u64)(unsigned long)screen_info.ext_lfb_base << 32;
+		ext_lfb_base = (u64)(unsigned long)si->ext_lfb_base << 32;
 		efifb_fix.smem_start |= ext_lfb_base;
 	}
 
@@ -417,10 +420,10 @@ static int efifb_probe(struct platform_device *dev)
 		efifb_fix.smem_start = bar_resource->start + bar_offset;
 	}
 
-	efifb_defined.bits_per_pixel = screen_info.lfb_depth;
-	efifb_defined.xres = screen_info.lfb_width;
-	efifb_defined.yres = screen_info.lfb_height;
-	efifb_fix.line_length = screen_info.lfb_linelength;
+	efifb_defined.bits_per_pixel = si->lfb_depth;
+	efifb_defined.xres = si->lfb_width;
+	efifb_defined.yres = si->lfb_height;
+	efifb_fix.line_length = si->lfb_linelength;
 
 	/*   size_vmode -- that is the amount of memory needed for the
 	 *                 used video mode, i.e. the minimum amount of
@@ -430,7 +433,7 @@ static int efifb_probe(struct platform_device *dev)
 	/*   size_total -- all video memory we have. Used for
 	 *                 entries, ressource allocation and bounds
 	 *                 checking. */
-	size_total = screen_info.lfb_size;
+	size_total = si->lfb_size;
 	if (size_total < size_vmode)
 		size_total = size_vmode;
 
@@ -512,7 +515,7 @@ static int efifb_probe(struct platform_device *dev)
 	pr_info("efifb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
 	       efifb_defined.xres, efifb_defined.yres,
 	       efifb_defined.bits_per_pixel, efifb_fix.line_length,
-	       screen_info.pages);
+	       si->pages);
 
 	efifb_defined.xres_virtual = efifb_defined.xres;
 	efifb_defined.yres_virtual = efifb_fix.smem_len /
@@ -526,26 +529,26 @@ static int efifb_probe(struct platform_device *dev)
 	efifb_defined.left_margin  = (efifb_defined.xres / 8) & 0xf8;
 	efifb_defined.hsync_len    = (efifb_defined.xres / 8) & 0xf8;
 
-	efifb_defined.red.offset    = screen_info.red_pos;
-	efifb_defined.red.length    = screen_info.red_size;
-	efifb_defined.green.offset  = screen_info.green_pos;
-	efifb_defined.green.length  = screen_info.green_size;
-	efifb_defined.blue.offset   = screen_info.blue_pos;
-	efifb_defined.blue.length   = screen_info.blue_size;
-	efifb_defined.transp.offset = screen_info.rsvd_pos;
-	efifb_defined.transp.length = screen_info.rsvd_size;
+	efifb_defined.red.offset    = si->red_pos;
+	efifb_defined.red.length    = si->red_size;
+	efifb_defined.green.offset  = si->green_pos;
+	efifb_defined.green.length  = si->green_size;
+	efifb_defined.blue.offset   = si->blue_pos;
+	efifb_defined.blue.length   = si->blue_size;
+	efifb_defined.transp.offset = si->rsvd_pos;
+	efifb_defined.transp.length = si->rsvd_size;
 
 	pr_info("efifb: %s: "
 	       "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
 	       "Truecolor",
-	       screen_info.rsvd_size,
-	       screen_info.red_size,
-	       screen_info.green_size,
-	       screen_info.blue_size,
-	       screen_info.rsvd_pos,
-	       screen_info.red_pos,
-	       screen_info.green_pos,
-	       screen_info.blue_pos);
+	       si->rsvd_size,
+	       si->red_size,
+	       si->green_size,
+	       si->blue_size,
+	       si->rsvd_pos,
+	       si->red_pos,
+	       si->green_pos,
+	       si->blue_pos);
 
 	efifb_fix.ypanstep  = 0;
 	efifb_fix.ywrapstep = 0;
-- 
2.43.0

[PATCH 2/4] fbdev/efifb: Use screen_info pointer from device

[Thomas Zimmermann]

Use the screen_info instance from the device instead of dereferencing
the global screen_info state. Decouples the driver from per-architecture
code. Duplicated the screen_info data, so that efifb can modify it at
will.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/efifb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index 6cbb65bbe1110..d0ce357ff2684 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -358,7 +358,7 @@ static u64 bar_offset;
 
 static int efifb_probe(struct platform_device *dev)
 {
-	struct screen_info *si = &screen_info;
+	struct screen_info *si;
 	struct fb_info *info;
 	struct efifb_par *par;
 	int err, orientation;
@@ -368,6 +368,13 @@ static int efifb_probe(struct platform_device *dev)
 	char *option = NULL;
 	efi_memory_desc_t md;
 
+	si = dev_get_platdata(&dev->dev);
+	if (!si)
+		return -ENODEV;
+	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
+	if (!si)
+		return -ENOMEM;
+
 	if (si->orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
 		return -ENODEV;
 
-- 
2.43.0

[PATCH 3/4] fbdev/vesafb: Replace references to global screen_info by local pointer

[Thomas Zimmermann]

Get the global screen_info's address once and access the data via
this pointer. Limits the use of global state.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/vesafb.c | 66 +++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 31 deletions(-)

diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
index c0edceea0a793..ea89accbec385 100644
--- a/drivers/video/fbdev/vesafb.c
+++ b/drivers/video/fbdev/vesafb.c
@@ -243,6 +243,7 @@ static int vesafb_setup(char *options)
 
 static int vesafb_probe(struct platform_device *dev)
 {
+	struct screen_info *si = &screen_info;
 	struct fb_info *info;
 	struct vesafb_par *par;
 	int i, err;
@@ -255,17 +256,17 @@ static int vesafb_probe(struct platform_device *dev)
 	fb_get_options("vesafb", &option);
 	vesafb_setup(option);
 
-	if (screen_info.orig_video_isVGA != VIDEO_TYPE_VLFB)
+	if (si->orig_video_isVGA != VIDEO_TYPE_VLFB)
 		return -ENODEV;
 
-	vga_compat = (screen_info.capabilities & 2) ? 0 : 1;
-	vesafb_fix.smem_start = screen_info.lfb_base;
-	vesafb_defined.bits_per_pixel = screen_info.lfb_depth;
+	vga_compat = (si->capabilities & 2) ? 0 : 1;
+	vesafb_fix.smem_start = si->lfb_base;
+	vesafb_defined.bits_per_pixel = si->lfb_depth;
 	if (15 == vesafb_defined.bits_per_pixel)
 		vesafb_defined.bits_per_pixel = 16;
-	vesafb_defined.xres = screen_info.lfb_width;
-	vesafb_defined.yres = screen_info.lfb_height;
-	vesafb_fix.line_length = screen_info.lfb_linelength;
+	vesafb_defined.xres = si->lfb_width;
+	vesafb_defined.yres = si->lfb_height;
+	vesafb_fix.line_length = si->lfb_linelength;
 	vesafb_fix.visual   = (vesafb_defined.bits_per_pixel == 8) ?
 		FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_TRUECOLOR;
 
@@ -277,7 +278,7 @@ static int vesafb_probe(struct platform_device *dev)
 	/*   size_total -- all video memory we have. Used for mtrr
 	 *                 entries, resource allocation and bounds
 	 *                 checking. */
-	size_total = screen_info.lfb_size * 65536;
+	size_total = si->lfb_size * 65536;
 	if (vram_total)
 		size_total = vram_total * 1024 * 1024;
 	if (size_total < size_vmode)
@@ -297,7 +298,7 @@ static int vesafb_probe(struct platform_device *dev)
 	vesafb_fix.smem_len = size_remap;
 
 #ifndef __i386__
-	screen_info.vesapm_seg = 0;
+	si->vesapm_seg = 0;
 #endif
 
 	if (!request_mem_region(vesafb_fix.smem_start, size_total, "vesafb")) {
@@ -317,23 +318,26 @@ static int vesafb_probe(struct platform_device *dev)
 	par = info->par;
 	info->pseudo_palette = par->pseudo_palette;
 
-	par->base = screen_info.lfb_base;
+	par->base = si->lfb_base;
 	par->size = size_total;
 
 	printk(KERN_INFO "vesafb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
-	       vesafb_defined.xres, vesafb_defined.yres, vesafb_defined.bits_per_pixel, vesafb_fix.line_length, screen_info.pages);
+	       vesafb_defined.xres, vesafb_defined.yres, vesafb_defined.bits_per_pixel,
+	       vesafb_fix.line_length, si->pages);
 
-	if (screen_info.vesapm_seg) {
+	if (si->vesapm_seg) {
 		printk(KERN_INFO "vesafb: protected mode interface info at %04x:%04x\n",
-		       screen_info.vesapm_seg,screen_info.vesapm_off);
+		       si->vesapm_seg, si->vesapm_off);
 	}
 
-	if (screen_info.vesapm_seg < 0xc000)
+	if (si->vesapm_seg < 0xc000)
 		ypan = pmi_setpal = 0; /* not available or some DOS TSR ... */
 
 	if (ypan || pmi_setpal) {
+		unsigned long pmi_phys;
 		unsigned short *pmi_base;
-		pmi_base  = (unsigned short*)phys_to_virt(((unsigned long)screen_info.vesapm_seg << 4) + screen_info.vesapm_off);
+		pmi_phys  = ((unsigned long)si->vesapm_seg << 4) + si->vesapm_off;
+		pmi_base  = (unsigned short *)phys_to_virt(pmi_phys);
 		pmi_start = (void*)((char*)pmi_base + pmi_base[1]);
 		pmi_pal   = (void*)((char*)pmi_base + pmi_base[2]);
 		printk(KERN_INFO "vesafb: pmi: set display start = %p, set palette = %p\n",pmi_start,pmi_pal);
@@ -377,14 +381,14 @@ static int vesafb_probe(struct platform_device *dev)
 	vesafb_defined.left_margin  = (vesafb_defined.xres / 8) & 0xf8;
 	vesafb_defined.hsync_len    = (vesafb_defined.xres / 8) & 0xf8;
 
-	vesafb_defined.red.offset    = screen_info.red_pos;
-	vesafb_defined.red.length    = screen_info.red_size;
-	vesafb_defined.green.offset  = screen_info.green_pos;
-	vesafb_defined.green.length  = screen_info.green_size;
-	vesafb_defined.blue.offset   = screen_info.blue_pos;
-	vesafb_defined.blue.length   = screen_info.blue_size;
-	vesafb_defined.transp.offset = screen_info.rsvd_pos;
-	vesafb_defined.transp.length = screen_info.rsvd_size;
+	vesafb_defined.red.offset    = si->red_pos;
+	vesafb_defined.red.length    = si->red_size;
+	vesafb_defined.green.offset  = si->green_pos;
+	vesafb_defined.green.length  = si->green_size;
+	vesafb_defined.blue.offset   = si->blue_pos;
+	vesafb_defined.blue.length   = si->blue_size;
+	vesafb_defined.transp.offset = si->rsvd_pos;
+	vesafb_defined.transp.length = si->rsvd_size;
 
 	if (vesafb_defined.bits_per_pixel <= 8) {
 		depth = vesafb_defined.green.length;
@@ -399,14 +403,14 @@ static int vesafb_probe(struct platform_device *dev)
 	       (vesafb_defined.bits_per_pixel > 8) ?
 	       "Truecolor" : (vga_compat || pmi_setpal) ?
 	       "Pseudocolor" : "Static Pseudocolor",
-	       screen_info.rsvd_size,
-	       screen_info.red_size,
-	       screen_info.green_size,
-	       screen_info.blue_size,
-	       screen_info.rsvd_pos,
-	       screen_info.red_pos,
-	       screen_info.green_pos,
-	       screen_info.blue_pos);
+	       si->rsvd_size,
+	       si->red_size,
+	       si->green_size,
+	       si->blue_size,
+	       si->rsvd_pos,
+	       si->red_pos,
+	       si->green_pos,
+	       si->blue_pos);
 
 	vesafb_fix.ypanstep  = ypan     ? 1 : 0;
 	vesafb_fix.ywrapstep = (ypan>1) ? 1 : 0;
-- 
2.43.0

[PATCH 4/4] fbdev/vesafb: Use screen_info pointer from device

[Thomas Zimmermann]

Use the screen_info instance from the device instead of dereferencing
the global screen_info state. Decouples the driver from per-architecture
code. Duplicated the screen_info data, so that vesafb can modify it at
will.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/vesafb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
index ea89accbec385..8912b16db75a1 100644
--- a/drivers/video/fbdev/vesafb.c
+++ b/drivers/video/fbdev/vesafb.c
@@ -243,7 +243,7 @@ static int vesafb_setup(char *options)
 
 static int vesafb_probe(struct platform_device *dev)
 {
-	struct screen_info *si = &screen_info;
+	struct screen_info *si;
 	struct fb_info *info;
 	struct vesafb_par *par;
 	int i, err;
@@ -252,6 +252,13 @@ static int vesafb_probe(struct platform_device *dev)
 	unsigned int size_total;
 	char *option = NULL;
 
+	si = dev_get_platdata(&dev->dev);
+	if (!si)
+		return -ENODEV;
+	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
+	if (!si)
+		return -ENOMEM;
+
 	/* ignore error return of fb_get_options */
 	fb_get_options("vesafb", &option);
 	vesafb_setup(option);
-- 
2.43.0

Re: [PATCH 1/4] fbdev/efifb: Replace references to global screen_info by local pointer

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann@suse.de> writes:

> Get the global screen_info's address once and access the data via
> this pointer. Limits the use of global state.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat

Re: [PATCH 2/4] fbdev/efifb: Use screen_info pointer from device

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann@suse.de> writes:

> Use the screen_info instance from the device instead of dereferencing
> the global screen_info state. Decouples the driver from per-architecture
> code. Duplicated the screen_info data, so that efifb can modify it at
> will.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

[...]

> +	si = dev_get_platdata(&dev->dev);
> +	if (!si)

I would add a comment that this platform data is set when the device is
registered by sysfb.

> +		return -ENODEV;
> +	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
> +	if (!si)
> +		return -ENOMEM;
> +

Why a copy? In any case maybe the global screen_info should be duplicated
when is set as the device platform data in sysfb_init() ?

I agree with the direction of the patch though, so whatever you decide:

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat

Re: [PATCH 4/4] fbdev/vesafb: Use screen_info pointer from device

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann@suse.de> writes:

> Use the screen_info instance from the device instead of dereferencing
> the global screen_info state. Decouples the driver from per-architecture
> code. Duplicated the screen_info data, so that vesafb can modify it at
> will.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Same comments that in patch #2. But regardless:

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat

Re: [PATCH 2/4] fbdev/efifb: Use screen_info pointer from device

[Thomas Zimmermann]

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Hi Javier

Am 01.12.23 um 09:54 schrieb Javier Martinez Canillas:
> Thomas Zimmermann <tzimmermann@suse.de> writes:
> 
>> Use the screen_info instance from the device instead of dereferencing
>> the global screen_info state. Decouples the driver from per-architecture
>> code. Duplicated the screen_info data, so that efifb can modify it at
>> will.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
> 
> [...]
> 
>> +	si = dev_get_platdata(&dev->dev);
>> +	if (!si)
> 
> I would add a comment that this platform data is set when the device is
> registered by sysfb.
> 
>> +		return -ENODEV;
>> +	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
>> +	if (!si)
>> +		return -ENOMEM;
>> +
> 
> Why a copy? In any case maybe the global screen_info should be duplicated
> when is set as the device platform data in sysfb_init() ?

We get our own copy of the global screen_info as platform-device data. 
Efifb modifies some of the values in our copy in efifb_setup(). If 
probing afterwards fails, the kernel might try a different driver, which 
would then operate on the values modified by efifb. Hence, there's this 
internal copy. The situation with vesafb is similar.

Best regards
Thomas

> 
> I agree with the direction of the patch though, so whatever you decide:
> 
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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Re: [PATCH 2/4] fbdev/efifb: Use screen_info pointer from device

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann@suse.de> writes:

> Hi Javier
>
> Am 01.12.23 um 09:54 schrieb Javier Martinez Canillas:
>> Thomas Zimmermann <tzimmermann@suse.de> writes:
>> 
>>> Use the screen_info instance from the device instead of dereferencing
>>> the global screen_info state. Decouples the driver from per-architecture
>>> code. Duplicated the screen_info data, so that efifb can modify it at
>>> will.
>>>
>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>> ---
>> 
>> [...]
>> 
>>> +	si = dev_get_platdata(&dev->dev);
>>> +	if (!si)
>> 
>> I would add a comment that this platform data is set when the device is
>> registered by sysfb.
>> 
>>> +		return -ENODEV;
>>> +	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
>>> +	if (!si)
>>> +		return -ENOMEM;
>>> +
>> 
>> Why a copy? In any case maybe the global screen_info should be duplicated
>> when is set as the device platform data in sysfb_init() ?
>
> We get our own copy of the global screen_info as platform-device data.

Ah, I didn't notice that platform_device_add_data() already did a kmemdup().

> Efifb modifies some of the values in our copy in efifb_setup(). If 
> probing afterwards fails, the kernel might try a different driver, which 
> would then operate on the values modified by efifb. Hence, there's this 
> internal copy. The situation with vesafb is similar.
>

I see what you mean. I was thinking that the same device coulnd't be match
to a different driver anyways but it's true that a fail to would make that
possible.

> Best regards
> Thomas
>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat