* [PATCH 04/13] drivers/video: fsl-diu-fb: fix compilation warning
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
Fix this compilation warning in the Freescale DIU framebuffer driver:
warning: 'dummy_ad_addr' may be used uninitialized in this function
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 226f4bc..6c544cf 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1429,7 +1429,7 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
{
struct device_node *np = ofdev->dev.of_node;
struct mfb_info *mfbi;
- phys_addr_t dummy_ad_addr;
+ phys_addr_t dummy_ad_addr = 0;
int ret, i, error = 0;
struct resource res;
struct fsl_diu_data *machine_data;
--
1.7.3.4
^ permalink raw reply related
* [PATCH 05/13] drivers/video: fsl-diu-fb: improve device tree usage
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
Implement various improvements to the way the Freescale DIU framebuffer
driver access the device tree.
1) Use of_iomap() instead of of_address_to_resource() and ioremap()
2) Use be32_to_cpup() instead of directly dereferencing the device_node
pointer.
3) Rename variable 'ofdev' to 'pdev' to avoid any confusion that it's
a platform_device pointer, not an of_device pointer (of_device no
longer exists).
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 65 ++++++++++++++++---------------------------
1 files changed, 24 insertions(+), 41 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 6c544cf..96417ab 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1425,13 +1425,12 @@ static ssize_t show_monitor(struct device *device,
return 0;
}
-static int __devinit fsl_diu_probe(struct platform_device *ofdev)
+static int __devinit fsl_diu_probe(struct platform_device *pdev)
{
- struct device_node *np = ofdev->dev.of_node;
+ struct device_node *np = pdev->dev.of_node;
struct mfb_info *mfbi;
phys_addr_t dummy_ad_addr = 0;
int ret, i, error = 0;
- struct resource res;
struct fsl_diu_data *machine_data;
int diu_mode;
@@ -1441,9 +1440,9 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
for (i = 0; i < ARRAY_SIZE(machine_data->fsl_diu_info); i++) {
machine_data->fsl_diu_info[i] - framebuffer_alloc(sizeof(struct mfb_info), &ofdev->dev);
+ framebuffer_alloc(sizeof(struct mfb_info), &pdev->dev);
if (!machine_data->fsl_diu_info[i]) {
- dev_err(&ofdev->dev, "cannot allocate memory\n");
+ dev_err(&pdev->dev, "cannot allocate memory\n");
ret = -ENOMEM;
goto error2;
}
@@ -1463,19 +1462,9 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
}
}
- ret = of_address_to_resource(np, 0, &res);
- if (ret) {
- dev_err(&ofdev->dev, "could not obtain DIU address\n");
- goto error;
- }
- if (!res.start) {
- dev_err(&ofdev->dev, "invalid DIU address\n");
- goto error;
- }
-
- dr.diu_reg = ioremap(res.start, sizeof(struct diu));
+ dr.diu_reg = of_iomap(np, 0);
if (!dr.diu_reg) {
- dev_err(&ofdev->dev, "Err: can't map DIU registers!\n");
+ dev_err(&pdev->dev, "cannot map DIU registers\n");
ret = -EFAULT;
goto error2;
}
@@ -1488,25 +1477,25 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
machine_data->irq = irq_of_parse_and_map(np, 0);
if (!machine_data->irq) {
- dev_err(&ofdev->dev, "could not get DIU IRQ\n");
+ dev_err(&pdev->dev, "could not get DIU IRQ\n");
ret = -EINVAL;
goto error;
}
machine_data->monitor_port = monitor_port;
/* Area descriptor memory pool aligns to 64-bit boundary */
- if (allocate_buf(&ofdev->dev, &pool.ad,
+ if (allocate_buf(&pdev->dev, &pool.ad,
sizeof(struct diu_ad) * FSL_AOI_NUM, 8))
return -ENOMEM;
/* Get memory for Gamma Table - 32-byte aligned memory */
- if (allocate_buf(&ofdev->dev, &pool.gamma, 768, 32)) {
+ if (allocate_buf(&pdev->dev, &pool.gamma, 768, 32)) {
ret = -ENOMEM;
goto error;
}
/* For performance, cursor bitmap buffer aligns to 32-byte boundary */
- if (allocate_buf(&ofdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2,
+ if (allocate_buf(&pdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2,
32)) {
ret = -ENOMEM;
goto error;
@@ -1548,16 +1537,13 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
mfbi->ad->paddr = pool.ad.paddr + i * sizeof(struct diu_ad);
ret = install_fb(machine_data->fsl_diu_info[i]);
if (ret) {
- dev_err(&ofdev->dev,
- "Failed to register framebuffer %d\n",
- i);
+ dev_err(&pdev->dev, "could not register fb %d\n", i);
goto error;
}
}
if (request_irq_local(machine_data->irq)) {
- dev_err(machine_data->fsl_diu_info[0]->dev,
- "could not request irq for diu.");
+ dev_err(&pdev->dev, "could not claim irq\n");
goto error;
}
@@ -1569,12 +1555,11 @@ static int __devinit fsl_diu_probe(struct platform_device *ofdev)
error = device_create_file(machine_data->fsl_diu_info[0]->dev,
&machine_data->dev_attr);
if (error) {
- dev_err(machine_data->fsl_diu_info[0]->dev,
- "could not create sysfs %s file\n",
+ dev_err(&pdev->dev, "could not create sysfs file %s\n",
machine_data->dev_attr.attr.name);
}
- dev_set_drvdata(&ofdev->dev, machine_data);
+ dev_set_drvdata(&pdev->dev, machine_data);
return 0;
error:
@@ -1582,12 +1567,12 @@ error:
i > 0; i--)
uninstall_fb(machine_data->fsl_diu_info[i - 1]);
if (pool.ad.vaddr)
- free_buf(&ofdev->dev, &pool.ad,
+ free_buf(&pdev->dev, &pool.ad,
sizeof(struct diu_ad) * FSL_AOI_NUM, 8);
if (pool.gamma.vaddr)
- free_buf(&ofdev->dev, &pool.gamma, 768, 32);
+ free_buf(&pdev->dev, &pool.gamma, 768, 32);
if (pool.cursor.vaddr)
- free_buf(&ofdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2,
+ free_buf(&pdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2,
32);
if (machine_data->dummy_aoi_virt)
fsl_diu_free(machine_data->dummy_aoi_virt, 64);
@@ -1602,25 +1587,23 @@ error2:
return ret;
}
-
-static int fsl_diu_remove(struct platform_device *ofdev)
+static int fsl_diu_remove(struct platform_device *pdev)
{
struct fsl_diu_data *machine_data;
int i;
- machine_data = dev_get_drvdata(&ofdev->dev);
+ machine_data = dev_get_drvdata(&pdev->dev);
disable_lcdc(machine_data->fsl_diu_info[0]);
free_irq_local(machine_data->irq);
for (i = ARRAY_SIZE(machine_data->fsl_diu_info); i > 0; i--)
uninstall_fb(machine_data->fsl_diu_info[i - 1]);
if (pool.ad.vaddr)
- free_buf(&ofdev->dev, &pool.ad,
+ free_buf(&pdev->dev, &pool.ad,
sizeof(struct diu_ad) * FSL_AOI_NUM, 8);
if (pool.gamma.vaddr)
- free_buf(&ofdev->dev, &pool.gamma, 768, 32);
+ free_buf(&pdev->dev, &pool.gamma, 768, 32);
if (pool.cursor.vaddr)
- free_buf(&ofdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2,
- 32);
+ free_buf(&pdev->dev, &pool.cursor, MAX_CURS * MAX_CURS * 2, 32);
if (machine_data->dummy_aoi_virt)
fsl_diu_free(machine_data->dummy_aoi_virt, 64);
iounmap(dr.diu_reg);
@@ -1722,7 +1705,7 @@ static int __init fsl_diu_init(void)
* Freescale PLRU requires 13/8 times the cache size to do a proper
* displacement flush
*/
- coherence_data_size = *prop * 13;
+ coherence_data_size = be32_to_cpup(prop) * 13;
coherence_data_size /= 8;
prop = of_get_property(np, "d-cache-line-size", NULL);
@@ -1732,7 +1715,7 @@ static int __init fsl_diu_init(void)
of_node_put(np);
return -ENODEV;
}
- d_cache_line_size = *prop;
+ d_cache_line_size = be32_to_cpup(prop);
of_node_put(np);
coherence_data = vmalloc(coherence_data_size);
--
1.7.3.4
^ permalink raw reply related
* [PATCH 06/13] drivers/video: fsl-diu-fb: remove redundant default video mode
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
The framebuffer layer already uses the first video mode defined in the
fb_videomode array as a default, so there's no need to duplicate the
first entry into a stand-alone structure.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 32 +++++++-------------------------
1 files changed, 7 insertions(+), 25 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 96417ab..c893954 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -36,26 +36,10 @@
#include "edid.h"
/*
- * These parameters give default parameters
- * for video output 1024x768,
- * FIXME - change timing to proper amounts
- * hsync 31.5kHz, vsync 60Hz
+ * List of supported video modes
+ *
+ * The first entry is the default video mode
*/
-static struct fb_videomode __devinitdata fsl_diu_default_mode = {
- .refresh = 60,
- .xres = 1024,
- .yres = 768,
- .pixclock = 15385,
- .left_margin = 160,
- .right_margin = 24,
- .upper_margin = 29,
- .lower_margin = 3,
- .hsync_len = 136,
- .vsync_len = 6,
- .sync = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
- .vmode = FB_VMODE_NONINTERLACED
-};
-
static struct fb_videomode __devinitdata fsl_diu_mode_db[] = {
{
.name = "1024x768-60",
@@ -1165,8 +1149,8 @@ static int __devinit install_fb(struct fb_info *info)
} else {
aoi_mode = init_aoi_mode;
}
- rc = fb_find_mode(&info->var, info, aoi_mode, db, dbsize,
- &fsl_diu_default_mode, default_bpp);
+ rc = fb_find_mode(&info->var, info, aoi_mode, db, dbsize, NULL,
+ default_bpp);
if (!rc) {
/*
* For plane 0 we continue and look into
@@ -1180,10 +1164,8 @@ static int __devinit install_fb(struct fb_info *info)
if (!has_default_mode) {
rc = fb_find_mode(&info->var, info, aoi_mode, fsl_diu_mode_db,
- ARRAY_SIZE(fsl_diu_mode_db),
- &fsl_diu_default_mode,
- default_bpp);
- if (rc > 0 && rc < 5)
+ ARRAY_SIZE(fsl_diu_mode_db), NULL, default_bpp);
+ if (rc)
has_default_mode = 1;
}
--
1.7.3.4
^ permalink raw reply related
* [PATCH 07/13] drivers/video: fsl-diu-fb: improve local variable usage in some functions
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
Clean up the local variable usage in request_irq_local() and allocate_buf().
This streamlines the code without affecting functionality.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 23 ++++++++++-------------
1 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index c893954..4d22399 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1265,14 +1265,14 @@ static irqreturn_t fsl_diu_isr(int irq, void *dev_id)
static int request_irq_local(int irq)
{
- unsigned long status, ints;
+ u32 ints;
struct diu *hw;
int ret;
hw = dr.diu_reg;
/* Read to clear the status */
- status = in_be32(&hw->int_status);
+ in_be32(&hw->int_status);
ret = request_irq(irq, fsl_diu_isr, 0, "diu", NULL);
if (!ret) {
@@ -1285,7 +1285,7 @@ static int request_irq_local(int irq)
ints |= INT_VSYNC_WB;
/* Read to clear the status */
- status = in_be32(&hw->int_status);
+ in_be32(&hw->int_status);
out_be32(&hw->int_mask, ints);
}
@@ -1336,23 +1336,20 @@ static int fsl_diu_resume(struct platform_device *ofdev)
static int allocate_buf(struct device *dev, struct diu_addr *buf, u32 size,
u32 bytes_align)
{
- u32 offset, ssize;
- u32 mask;
- dma_addr_t paddr = 0;
+ u32 offset;
+ dma_addr_t mask;
- ssize = size + bytes_align;
- buf->vaddr = dma_alloc_coherent(dev, ssize, &paddr, GFP_DMA |
- __GFP_ZERO);
+ buf->vaddr + dma_alloc_coherent(dev, size + bytes_align, &buf->paddr,
+ GFP_DMA | __GFP_ZERO);
if (!buf->vaddr)
return -ENOMEM;
- buf->paddr = (__u32) paddr;
-
mask = bytes_align - 1;
- offset = (u32)buf->paddr & mask;
+ offset = buf->paddr & mask;
if (offset) {
buf->offset = bytes_align - offset;
- buf->paddr = (u32)buf->paddr + offset;
+ buf->paddr = buf->paddr + offset;
} else
buf->offset = 0;
--
1.7.3.4
^ permalink raw reply related
* [PATCH 08/13] drivers/video: fsl-diu-fb: set the driver name to "fsl-diu-fb"
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
Use the name "fsl-diu-fb" in the Freescale DIU framebuffer driver
during registrations.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 4d22399..19bfbf5 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1274,7 +1274,7 @@ static int request_irq_local(int irq)
/* Read to clear the status */
in_be32(&hw->int_status);
- ret = request_irq(irq, fsl_diu_isr, 0, "diu", NULL);
+ ret = request_irq(irq, fsl_diu_isr, 0, "fsl-diu-fb", NULL);
if (!ret) {
ints = INT_PARERR | INT_LS_BF_VS;
#if !defined(CONFIG_NOT_COHERENT_CACHE)
@@ -1634,7 +1634,7 @@ MODULE_DEVICE_TABLE(of, fsl_diu_match);
static struct platform_driver fsl_diu_driver = {
.driver = {
- .name = "fsl_diu",
+ .name = "fsl-diu-fb",
.owner = THIS_MODULE,
.of_match_table = fsl_diu_match,
},
--
1.7.3.4
^ permalink raw reply related
* [PATCH 09/13] drivers/video: fsl-diu-fb: fix potential memcpy buffer overflow bug
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
It makes no sense to limit the size of a strncpy() to the length of
the source string.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 19bfbf5..3776949 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -655,7 +655,7 @@ static void set_fix(struct fb_info *info)
struct fb_var_screeninfo *var = &info->var;
struct mfb_info *mfbi = info->par;
- strncpy(fix->id, mfbi->id, strlen(mfbi->id));
+ strncpy(fix->id, mfbi->id, sizeof(fix->id));
fix->line_length = var->xres_virtual * var->bits_per_pixel / 8;
fix->type = FB_TYPE_PACKED_PIXELS;
fix->accel = FB_ACCEL_NONE;
--
1.7.3.4
^ permalink raw reply related
* [PATCH 10/13] drivers/video: fsl-diu-fb: fix memory leak on error
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
We were forgetting to unmap the video memory if fsl_diu_check_var() fails.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 3776949..c66f6ed 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1200,6 +1200,7 @@ static int __devinit install_fb(struct fb_info *info)
if (fsl_diu_check_var(&info->var, info)) {
dev_err(info->dev, "fsl_diu_check_var failed\n");
+ unmap_video_memory(info);
fb_dealloc_cmap(&info->cmap);
return -EINVAL;
}
--
1.7.3.4
^ permalink raw reply related
* [PATCH 11/13] drivers/video: fsl-diu-fb: use a normal for-loop to uninstall framebuffers
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
Uninstalling the framebuffers in reverse order is unnecessary and makes
the for-loop awkward.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
drivers/video/fsl-diu-fb.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index c66f6ed..5137fbb 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -1543,9 +1543,9 @@ static int __devinit fsl_diu_probe(struct platform_device *pdev)
return 0;
error:
- for (i = ARRAY_SIZE(machine_data->fsl_diu_info);
- i > 0; i--)
- uninstall_fb(machine_data->fsl_diu_info[i - 1]);
+ for (i = 0; i < ARRAY_SIZE(machine_data->fsl_diu_info); i++)
+ uninstall_fb(machine_data->fsl_diu_info[i]);
+
if (pool.ad.vaddr)
free_buf(&pdev->dev, &pool.ad,
sizeof(struct diu_ad) * FSL_AOI_NUM, 8);
@@ -1575,8 +1575,8 @@ static int fsl_diu_remove(struct platform_device *pdev)
machine_data = dev_get_drvdata(&pdev->dev);
disable_lcdc(machine_data->fsl_diu_info[0]);
free_irq_local(machine_data->irq);
- for (i = ARRAY_SIZE(machine_data->fsl_diu_info); i > 0; i--)
- uninstall_fb(machine_data->fsl_diu_info[i - 1]);
+ for (i = 0; i < ARRAY_SIZE(machine_data->fsl_diu_info); i++)
+ uninstall_fb(machine_data->fsl_diu_info[i]);
if (pool.ad.vaddr)
free_buf(&pdev->dev, &pool.ad,
sizeof(struct diu_ad) * FSL_AOI_NUM, 8);
--
1.7.3.4
^ permalink raw reply related
* [PATCH 12/13] drivers/video: fsl-diu-fb: the video buffer is not I/O memory
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
The video buffer is not uncached memory-mapped I/O, so don't tag the virtual
address as __iomem. It's also not a u8*.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
include/linux/fsl-diu-fb.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/fsl-diu-fb.h b/include/linux/fsl-diu-fb.h
index 5ebffa6..35ac0c5 100644
--- a/include/linux/fsl-diu-fb.h
+++ b/include/linux/fsl-diu-fb.h
@@ -162,7 +162,7 @@ struct diu_hw {
};
struct diu_addr {
- __u8 __iomem *vaddr; /* Virtual address */
+ void *vaddr; /* Virtual address */
dma_addr_t paddr; /* Physical address */
__u32 offset;
};
--
1.7.3.4
^ permalink raw reply related
* [PATCH 13/13] drivers/video: fsl-diu-fb: remove unusued MEM_ALLOC_THRESHOLD
From: Timur Tabi @ 2011-09-15 21:44 UTC (permalink / raw)
To: linux-fbdev
If there was ever any code that used MEM_ALLOC_THRESHOLD, it was removed a
long time ago.
Signed-off-by: Timur Tabi <timur@freescale.com>
---
include/linux/fsl-diu-fb.h | 5 -----
1 files changed, 0 insertions(+), 5 deletions(-)
diff --git a/include/linux/fsl-diu-fb.h b/include/linux/fsl-diu-fb.h
index 35ac0c5..df23f59 100644
--- a/include/linux/fsl-diu-fb.h
+++ b/include/linux/fsl-diu-fb.h
@@ -20,11 +20,6 @@
#ifndef __FSL_DIU_FB_H__
#define __FSL_DIU_FB_H__
-/* Arbitrary threshold to determine the allocation method
- * See mpc8610fb_set_par(), map_video_memory(), and unmap_video_memory()
- */
-#define MEM_ALLOC_THRESHOLD (1024*768*4+32)
-
#include <linux/types.h>
struct mfb_chroma_key {
--
1.7.3.4
^ permalink raw reply related
* Re: Proposal for a low-level Linux display framework
From: Keith Packard @ 2011-09-16 0:55 UTC (permalink / raw)
To: Tomi Valkeinen
Cc: linux-fbdev, linux-kernel, dri-devel, linaro-dev, Clark, Rob,
Archit Taneja
In-Reply-To: <1316107275.23214.99.camel@deskari>
[-- Attachment #1: Type: text/plain, Size: 2162 bytes --]
On Thu, 15 Sep 2011 20:21:15 +0300, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> 2) panel drivers, handles panel specific things. Each panel may support
> custom commands and features, for which we need a dedicated driver. And
> this driver is not platform specific, but should work with any platform
> which has the output used with the panel.
Right, we've got DDC ports (which are just i2c) and DisplayPort aux
channel stuff.
The DDC stuff is abstracted out and shared across the drivers, but the
DisplayPort aux channel code is not -- it's duplicated in every output
driver.
> DSI bus is a half-duplex serial bus, and while it's designed for
> displays you could use it easily for any communication between the SoC
> and the peripheral.
Yeah, HDMI uses DDC for all kinds of crazy stuff in the CE world.
> The point is that we cannot have standard "MIPI DSI command mode panel
> driver" which would work for all DSI cmd mode panels, but we need (in
> the worst case) separate driver for each panel.
It sounds like we do want to share code for those bits, much like we
have DDC split out now. And, we should do something about the
DisplayPort aux channel stuff to avoid duplicating it everywhere.
I'm not sure a common interface to all of these different
channels makes sense, but surely a DSI library and an aux channel
library would fit nicely alongside the existing DDC library.
I suspect helper functions would be a good model to follow, rather than
trying to create a whole new device infrastructure; some of the
communication paths aren't easily separable from the underlying output
devices.
Oh, I think you're also trying to get at how we expose some of these
controls outside of the display driver -- right now, they're mostly
exposed as properties on the output device. Things like backlight
brightness, a million analog TV output values, dithering control and
other more esoteric controls.
DRM properties include booleans, enumerations, integer ranges and chunks
of binary data. Some are read-only (like EDID data), some are writable
(like overscan values).
--
keith.packard@intel.com
[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Keith Packard @ 2011-09-16 4:53 UTC (permalink / raw)
To: Florian Tobias Schandinat, Alex Deucher
Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja,
Clark, Rob
In-Reply-To: <4E724659.5080709@gmx.de>
[-- Attachment #1: Type: text/plain, Size: 1676 bytes --]
On Thu, 15 Sep 2011 18:39:21 +0000, Florian Tobias Schandinat <FlorianSchandinat@gmx.de> wrote:
> Well, I'm not against sharing the code and not against taking DRM's current
> implementation as a base but the steps required to make it generally acceptable
> would be to split it of, probably as a standalone module and strip all DRM
> specific things off. Than all things that require EDID can use it, DRM can add
> DRM-specific things on top and fb can add fb-specific things.
The rendering portions of the DRM drivers are all device-specific. The
core DRM ioctls are largely about providing some sharing control over
the device, mapping memory around and mode setting.
> One of my biggest problems with KMS is that it has (naturally) a lot more
> complexity than the fb API which leads to instability.
The mode setting portions are of necessity the same. The KMS API exposes
more functionality for mode setting, but doesn't actually require any
additional hardware-specific knowledge. You still have to be able to
bring the hardware up from power on and light up every connected
monitor.
However, if you want acceleration, you're going to run into bugs that
crash the machine. It's a sad reality that graphics hardware just isn't
able to recover cleanly in all cases from programmer errors, and that
includes errors that come from user mode.
Hardware is improving in this area, and reset is getting more reliable
than it used to be. But, until we can context switch the graphics
hardware at arbitrary points during execution, we're kinda stuck with
using the really big reset hammer when programs go awry.
--
keith.packard@intel.com
[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Tomi Valkeinen @ 2011-09-16 6:38 UTC (permalink / raw)
To: Keith Packard
Cc: linux-fbdev, linux-kernel, dri-devel, linaro-dev, Clark, Rob,
Archit Taneja
In-Reply-To: <yunfwjxwbjq.fsf@aiko.keithp.com>
On Thu, 2011-09-15 at 19:55 -0500, Keith Packard wrote:
> On Thu, 15 Sep 2011 20:21:15 +0300, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>
> > 2) panel drivers, handles panel specific things. Each panel may support
> > custom commands and features, for which we need a dedicated driver. And
> > this driver is not platform specific, but should work with any platform
> > which has the output used with the panel.
>
> Right, we've got DDC ports (which are just i2c) and DisplayPort aux
> channel stuff.
>
> The DDC stuff is abstracted out and shared across the drivers, but the
> DisplayPort aux channel code is not -- it's duplicated in every output
> driver.
I feel that you are still talking about the output driver, not the
panel. DDC and DP aux are part of the connector-entity in DRM, right?
But there's no separate display-entity behind the connector, which would
handle the peculiarities for a particular panel/display, say DSI panel
model L33T from AcmeCorp.
So, as I see it, DDC and DP aux are on the output driver, and the panel
driver uses those to do whatever is needed for a particular panel.
> > DSI bus is a half-duplex serial bus, and while it's designed for
> > displays you could use it easily for any communication between the SoC
> > and the peripheral.
>
> Yeah, HDMI uses DDC for all kinds of crazy stuff in the CE world.
But that is still more or less standard HDMI stuff, isn't it? So you
implement it once for HDMI, and then it works with all HDMI monitors?
Or is there some way to implement custom behavior for one particular
HDMI monitor? Is this custom behavior in a kernel driver or handled in
userspace?
> > The point is that we cannot have standard "MIPI DSI command mode panel
> > driver" which would work for all DSI cmd mode panels, but we need (in
> > the worst case) separate driver for each panel.
>
> It sounds like we do want to share code for those bits, much like we
> have DDC split out now. And, we should do something about the
> DisplayPort aux channel stuff to avoid duplicating it everywhere.
Yep. What I had in mind for DSI with my low-level fmwk would be a
mipi_dsi component that offers services to use the DSI bus. Each
platform which supports DSI would implement the DSI support for their
HW. Then the DSI panel driver could do things like:
dsi->write(dev, virtual_channel_id, buf, len);
dsi->set_max_return_packet_size(dev, 10);
dsi->read(dev, virtual_channel_id, read_cmd, recv_buf, len);
An example DSI command mode panel driver can be found from
drivers/video/omap2/displays/panel-taal.c, which uses omapdss' dsi
functions directly but could quite easily use a common DSI interface and
thus be platform independent.
> I'm not sure a common interface to all of these different
> channels makes sense, but surely a DSI library and an aux channel
> library would fit nicely alongside the existing DDC library.
What do you mean with "channel"? Any video or command bus going to the
display? Yes, I think they are quite different and I don't see a point
in trying to make a common interface for them.
DSI is in many ways a real bus. You can connect multiple peripherals to
one DSI bus (but it needs a DSI hub), and communicate with them by using
their virtual channel ID. And quite often there are DSI chips that
transform the DSI packets to some other form. Some real example
configurations:
Plain DSI panel:
[SoC] ---DSI--- [DSI panel]
DSI-2-DisplayPort converter chip:
[SoC] ---DSI--- [DSI chip] ---DP--- [DP monitor]
DSI buffer chip supporting to DSI panels:
[SoC] ---DSI--- [DSI chip] +--DSI--- [DSI panel 1]
|--DSI--- [DSI panel 2]
It would be nice to be able to model this somehow neatly with device
drivers. For example, the DSI panel from the first example could be used
in the two-panel configuration, and if (and when) the panel requires
custom configuration, the same panel driver could be used in both cases.
In the first case the panel driver would use DSI support from the Soc,
in the third case the panel driver would use the DSI support from the
DSI chip (which would, in turn, use DSI support from the SoC).
Tomi
^ permalink raw reply
* Re: [PATCHv2 09/15] OMAP: DSS2: HDMI: implement detect()
From: K, Mythri P @ 2011-09-16 12:53 UTC (permalink / raw)
To: Tomi Valkeinen; +Cc: Rob Clark, linux-omap, linux-fbdev, archit
In-Reply-To: <1316068371.1880.25.camel@deskari>
Hi,
On Thu, Sep 15, 2011 at 12:02 PM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> On Thu, 2011-09-15 at 11:54 +0530, K, Mythri P wrote:
>> Hi,
>>
>> On Thu, Sep 15, 2011 at 11:27 AM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>> > On Thu, 2011-09-15 at 11:11 +0530, K, Mythri P wrote:
>> >> Hi,
>> >>
>> >> On Wed, Sep 14, 2011 at 7:41 PM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>> >
>> >> > Yes, you are right, detect() does not "know" if the monitor has changed
>> >> > between polls, so both notification and polling are needed. I
>> >> > implemented only polling as there's no HPD event mechanism yet in
>> >> > omapdss, and also because this was simple and gives DRM basic ability to
>> >> > detect a monitor.
>> >> >
>> >> If it is needed for DRM then it is fine, but with detect renamed to
>> >> poll. By next week i should have a patch ready for HPD event
>> >> mechanism.
>> >
>> > What is wrong with "detect"? It detects if there's a display connected.
>> > It can be used in polling manner, trying it every n seconds, but it
>> > should also be used even if you use HPD event. I think the normal
>> > sequence would be something like:
>> >
>> > 1) register HPD event
>> > 2) use detect() to see if a monitor is already connected
>> >
>> I guess polling ever few seconds to detect would be waste of CPU
>> cycles when there is already a mechanism in the H/w to detect the
>> connection.
>
> Obviously. Polling is only used if hot-plug-detect is not available. But
> detect function can be used even when HPD is available.
>
>> Current sequence :
>> Enable display ( Irrespective of whether the cable is connected on not)
>>
>> Sequence with HPD:
>> 1.Register for HPD connect.
>> 2.Enable display
>> 3.Notify DRM/Audio/Kernel component that wants to listen to this event.
>
> Why would you enable the display even if there's no monitor connected?
>
> And when the DRM starts, how does DRM know if the display was already
> connected? Would you send a HPD event when DRM registers to the event
> even if there's no actual plug-in event done (i.e. user actually
> connecting the cable)?
>
HPD event would be triggered only when the cable is connected , and
the EDID is ready to be read by the monitor. So the question enabling
display doesnt exist. When HDMI is enabled in the HPD mode it will be
in minimal power mode.
Yes then the driver will notify DRM/any module that cable(monitor) is
now connected.
> And just to clarify, my sequence example was from DRM's point of view.
> The HDMI driver shouldn't do anything before DRM/omapfb asks it to do
> something.
>
> Tomi
>
>
>
Thanks and regards,
Mythri.
^ permalink raw reply
* ***Western Union Payment Alert***
From: WESTERN UNION MONEY TRANSFER @ 2011-09-16 13:21 UTC (permalink / raw)
To: linux-fbdev
Good day,
I write to inform you that we have already sent you $5000.00 USD dollars through Western Union as we have been given the mandate to transfer your full compensation payment of $2.5Million Dollars via Western Union by the United Nations Government.So I decided to email you the MTCN and sender's name so you can pick up this $5000.00 USD to enable us send another $5000.00USD by tomorrow as you know we will be sending you only $5000.00 USD per day. Please pick up this information and run to any Western Union in your country to pick up the $5000.00 USD and call me back to send you another payment tomorrow. However we have noted you as a customer of western union money transfer.
Manager: Mr Alfred Dennis.
Email: wumt66655@yahoo.com.hk
Call or email me once you picked up this $5,000 USD today. Here is the western union information below.
SENDERS FIRST NAME :_____EMEKA
SENDER’S LAST NAME:_____ ONWUESI
MTCN:__________________ 6210476549
Amount;=___________________$5,000, USD
Test Question;= ___________Honest?
Test Answer;= _____________Trust
You have to track your Payment information on below Western union website before you locate any western union office.
https://wumt.westernunion.com/asp/orderStatus.asp?country=global
Regards,
Mr Alfred Dennis.
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Daniel Vetter @ 2011-09-16 14:17 UTC (permalink / raw)
To: Keith Packard
Cc: Tomi Valkeinen, linux-fbdev, linaro-dev, linux-kernel, dri-devel,
Archit Taneja, Clark, Rob
In-Reply-To: <yunfwjxwbjq.fsf@aiko.keithp.com>
On Thu, Sep 15, 2011 at 07:55:37PM -0500, Keith Packard wrote:
> I suspect helper functions would be a good model to follow, rather than
> trying to create a whole new device infrastructure; some of the
> communication paths aren't easily separable from the underlying output
> devices.
This. Helper functions make the driver writers life so much easier - if
your hw doesn't quite fit the model, you can usually extend functionality
with much less fuzz than if there's a full framework. This is also pretty
much the reason, why I don't like ttm.
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Alan Cox @ 2011-09-16 16:53 UTC (permalink / raw)
To: Keith Packard
Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja,
Clark, Rob
In-Reply-To: <yunfwjxwbjq.fsf@aiko.keithp.com>
> I'm not sure a common interface to all of these different
> channels makes sense, but surely a DSI library and an aux channel
> library would fit nicely alongside the existing DDC library.
DSI and the various other MIPI bits tend to be horribly panel and device
specific. In one sense yes its a standard with standard commands,
processes, queries etc, on the other a lot of stuff is oriented around
the 'its a fixed configuration unit we don't need to have queries' view.
There also tends to be a lot of vendor magic initialisation logic both
chipset and device dependant, and often 'plumbing dependant' on SoC
systems. This is doubly ugly with the I²C abstractions for DDC because
SoC systems are not above putting the DDC on a standard I²C port being
shared with other functionality.
> Oh, I think you're also trying to get at how we expose some of these
> controls outside of the display driver -- right now, they're mostly
> exposed as properties on the output device. Things like backlight
> brightness, a million analog TV output values, dithering control and
> other more esoteric controls.
This is how the MIPI handling in the GMA500 driver works, although the
existing code needs to be taken out and shot, which should be happening
soon. There is a lot, like panel initialisation which is however not
really going to fit a properties model.
Alan
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Felipe Contreras @ 2011-09-17 14:44 UTC (permalink / raw)
To: Alan Cox
Cc: Florian Tobias Schandinat, Alex Deucher, Keith Packard,
linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja,
Clark, Rob
In-Reply-To: <20110915195804.4e6d965b@lxorguk.ukuu.org.uk>
On Thu, Sep 15, 2011 at 9:58 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> One of my biggest problems with KMS is that it has (naturally) a lot more
>> complexity than the fb API which leads to instability. Basically it's very
>
> It shouldn't do - and a sample of one (your machine) is not a
> statistically valid set. Fb is pretty much ununsable in contrast on my
> main box, but that's not a statistically valid sample either.
>
> I'm not that convinced by the complexity either. For a simple video card
> setup such as those that the fb layer can kind of cope with (ie linear
> buffer, simple mode changes, no client rendering, no vblank flipping,
> limited mode management, no serious multi-head) a DRM driver is also
> pretty tiny and simple.
That's not true, many drivers work around the lack of features in the
fb API by providing custom interfaces. For example, in omapfb it's
possible to use the overlays from user-space, configure some YUV
format, do vsink, and multipages just fine:
https://github.com/felipec/gst-omapfb/blob/master/omapfb.c
It's perfect to render video clips. Of course, it would be even better
if those custom interfaces were merged into the fb API.
--
Felipe Contreras
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Rob Clark @ 2011-09-17 15:16 UTC (permalink / raw)
To: Felipe Contreras
Cc: linux-fbdev, linaro-dev, Florian Tobias Schandinat, linux-kernel,
dri-devel, Archit Taneja
In-Reply-To: <CAMP44s1ywhCV+FaudnwjwJUvj5Cf3_oz1M++kjXxRDGQpJ6-0w@mail.gmail.com>
On Sat, Sep 17, 2011 at 9:44 AM, Felipe Contreras
<felipe.contreras@gmail.com> wrote:
> On Thu, Sep 15, 2011 at 9:58 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>>> One of my biggest problems with KMS is that it has (naturally) a lot more
>>> complexity than the fb API which leads to instability. Basically it's very
>>
>> It shouldn't do - and a sample of one (your machine) is not a
>> statistically valid set. Fb is pretty much ununsable in contrast on my
>> main box, but that's not a statistically valid sample either.
>>
>> I'm not that convinced by the complexity either. For a simple video card
>> setup such as those that the fb layer can kind of cope with (ie linear
>> buffer, simple mode changes, no client rendering, no vblank flipping,
>> limited mode management, no serious multi-head) a DRM driver is also
>> pretty tiny and simple.
>
> That's not true, many drivers work around the lack of features in the
> fb API by providing custom interfaces. For example, in omapfb it's
> possible to use the overlays from user-space, configure some YUV
> format, do vsink, and multipages just fine:
>
> https://github.com/felipec/gst-omapfb/blob/master/omapfb.c
>
> It's perfect to render video clips. Of course, it would be even better
> if those custom interfaces were merged into the fb API.
fwiw, as was mentioned earlier in the thread, there is already an
effort underway for a standardized overlay interface for KMS:
http://lists.freedesktop.org/archives/dri-devel/2011-April/010559.html
Anyways, it is also possible to extend DRM drivers w/ custom API.. and
even possible extend the fbdev on top of DRM/KMS with custom
interfaces if you *really* wanted to. I have some patches somewhere
that add support a portion of the omapfb ioctls to the fbdev layer in
omapdrm driver for the benefit of some legacy display test app. If
someone really wanted to, I guess there is no reason that you couldn't
support all of the omapfb custom ioctls.
From userspace perspective, fbdev doesn't go away. It is just a
legacy interface provided on top of DRM/KMS driver mostly via helper
functions. With this approach, you get the richer KMS API (and all
the related plumbing for hotplug, EDID parsing, multi-head support,
flipping, etc) for userspace stuff that needs that, but can keep the
fbdev userspace interface for legacy apps. It is the best of both
worlds. There isn't really any good reason to propagate standalone
fbdev driver anymore.
BR,
-R
> --
> Felipe Contreras
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Florian Tobias Schandinat @ 2011-09-17 16:11 UTC (permalink / raw)
To: Rob Clark; +Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja
In-Reply-To: <CAF6AEGu2-O+2KuCrQPJ6-xejg8TCScrFVZSimgkAV_5Xs-bgkg@mail.gmail.com>
On 09/17/2011 03:16 PM, Rob Clark wrote:
>>From userspace perspective, fbdev doesn't go away. It is just a
> legacy interface provided on top of DRM/KMS driver mostly via helper
> functions. With this approach, you get the richer KMS API (and all
> the related plumbing for hotplug, EDID parsing, multi-head support,
> flipping, etc) for userspace stuff that needs that, but can keep the
> fbdev userspace interface for legacy apps. It is the best of both
> worlds. There isn't really any good reason to propagate standalone
> fbdev driver anymore.
I disagree. This depends on the functionality the hardware has, the desired
userspace and the manpower one has to do it. And of course if you just want fb
having fb via DRM/KMS has some overhead/bloat. It's perfectly okay to have just
an fb driver for devices that can't do more anyway.
And fb is no legacy interface but actively developed, just with other goals than
DRM/KMS is, it aims for stability and to provide a direct interface, not needing
any X or wayland crap.
Best regards,
Florian Tobias Schandinat
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Dave Airlie @ 2011-09-17 16:47 UTC (permalink / raw)
To: Florian Tobias Schandinat
Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja,
Rob Clark
In-Reply-To: <4E74C6C3.2000704@gmx.de>
>
> I disagree. This depends on the functionality the hardware has, the desired
> userspace and the manpower one has to do it. And of course if you just want fb
> having fb via DRM/KMS has some overhead/bloat. It's perfectly okay to have just
> an fb driver for devices that can't do more anyway.
> And fb is no legacy interface but actively developed, just with other goals than
> DRM/KMS is, it aims for stability and to provide a direct interface, not needing
> any X or wayland crap.
Stability is a total misnomer, whats worse is you know it. If you just
want to do software render your whole GUI whether you use KMS or fbdev
doesn't matter. Instability is only to do with GPU hardware
acceleration, whether fb or kms expose accel doesn't matter. So less
attitude please.
fbdev is totally uninteresting for any modern multi-output hardware
with an acceleration engine, you can't even memory manage the GPU
memory in any useful way, try resizing the fb console dynamically when
you've allocated the memory immediately following it in VRAM, you
can't as userspace has it direct mapped, with no way to remove the
mappings or repage them. Even now I'm still thinking we should do
kmscon without exposing the fbdev interface to userspace because the
whole mmap semantics are totally broken, look at the recent fb
handover race fixes.
Dave.
Dave.
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Rob Clark @ 2011-09-17 16:50 UTC (permalink / raw)
To: Florian Tobias Schandinat
Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja
In-Reply-To: <4E74C6C3.2000704@gmx.de>
On Sat, Sep 17, 2011 at 11:11 AM, Florian Tobias Schandinat
<FlorianSchandinat@gmx.de> wrote:
> On 09/17/2011 03:16 PM, Rob Clark wrote:
>>>From userspace perspective, fbdev doesn't go away. It is just a
>> legacy interface provided on top of DRM/KMS driver mostly via helper
>> functions. With this approach, you get the richer KMS API (and all
>> the related plumbing for hotplug, EDID parsing, multi-head support,
>> flipping, etc) for userspace stuff that needs that, but can keep the
>> fbdev userspace interface for legacy apps. It is the best of both
>> worlds. There isn't really any good reason to propagate standalone
>> fbdev driver anymore.
>
> I disagree. This depends on the functionality the hardware has, the desired
> userspace and the manpower one has to do it. And of course if you just want fb
> having fb via DRM/KMS has some overhead/bloat. It's perfectly okay to have just
> an fb driver for devices that can't do more anyway.
> And fb is no legacy interface but actively developed, just with other goals than
> DRM/KMS is, it aims for stability and to provide a direct interface, not needing
> any X or wayland crap.
Hmm, for simple enough devices, maybe fb is fine.. but if you are
covering a range of devices which include stuff with more
sophisticated userspace (X/wayland), then just doing DRM/KMS and using
the DRM fbdev helpers, vs doing both DRM/KMS and standalone fbdev..
well that seems like a no-brainer.
I still think, if you are starting a new driver, you should just go
ahead and use DRM/KMS.. a simple DRM/KMS driver that doesn't support
all the features is not so complex, and going this route future-proofs
you better when future generations of hardware gain more capabilities
and sw gain more requirements.
BR,
-R
>
> Best regards,
>
> Florian Tobias Schandinat
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Florian Tobias Schandinat @ 2011-09-17 18:15 UTC (permalink / raw)
To: Dave Airlie
Cc: Rob Clark, Felipe Contreras, Alan Cox, linaro-dev, linux-kernel,
dri-devel, Archit Taneja, linux-fbdev
In-Reply-To: <CAPM=9twmPVrBPmUuEuTYHSzjDGHtfsmiVX6cozpAFYEaV-NcCg@mail.gmail.com>
On 09/17/2011 04:47 PM, Dave Airlie wrote:
>>
>> I disagree. This depends on the functionality the hardware has, the desired
>> userspace and the manpower one has to do it. And of course if you just want fb
>> having fb via DRM/KMS has some overhead/bloat. It's perfectly okay to have just
>> an fb driver for devices that can't do more anyway.
>> And fb is no legacy interface but actively developed, just with other goals than
>> DRM/KMS is, it aims for stability and to provide a direct interface, not needing
>> any X or wayland crap.
>
> Stability is a total misnomer, whats worse is you know it. If you just
> want to do software render your whole GUI whether you use KMS or fbdev
> doesn't matter. Instability is only to do with GPU hardware
> acceleration, whether fb or kms expose accel doesn't matter. So less
> attitude please.
Is it? Well, okay, I don't want to use any acceleration that can crash my
machine, where can I select it, preferably as compile time option? I didn't find
such a thing for Intel or Radeon. Don't say, I should rely on userspace here or
use fbdev for this.
The thing is that the core fbdev API does not expose any acceleration to
userspace, maybe some drivers do via IOCTLs, but I hope that are only things
that can be done in a sane way, otherwise I'd consider it a bug. The story is
different for DRM/KMS, as I understand, as this was primarily for acceleration
and only recently got modesetting capabilities.
> fbdev is totally uninteresting for any modern multi-output hardware
> with an acceleration engine, you can't even memory manage the GPU
> memory in any useful way, try resizing the fb console dynamically when
> you've allocated the memory immediately following it in VRAM, you
> can't as userspace has it direct mapped, with no way to remove the
> mappings or repage them. Even now I'm still thinking we should do
> kmscon without exposing the fbdev interface to userspace because the
> whole mmap semantics are totally broken, look at the recent fb
> handover race fixes.
It's true that mmap can be PITA, but I don't see any real alternative given that
you want directly map video memory, especially on low end systems. And there are
ways around it, you can forbid mapping (though probably most userspace wouldn't
like it, I guess) or use any other solution like defio.
If you'd stop exposing the fbdev userspace interface it'd just harden my opinion
that KMS is a piece of trash and that I should avoid hardware that does not have
a native framebuffer driver. I think you shouldn't do this, as it's just a
disadvantage for your end users, but I personally do not really care.
Regards,
Florian Tobias Schandinat
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Dave Airlie @ 2011-09-17 18:23 UTC (permalink / raw)
To: Florian Tobias Schandinat
Cc: linux-fbdev, linaro-dev, linux-kernel, dri-devel, Archit Taneja,
Rob Clark
In-Reply-To: <4E74E3D6.8080401@gmx.de>
>
> Is it? Well, okay, I don't want to use any acceleration that can crash my
> machine, where can I select it, preferably as compile time option? I didn't find
> such a thing for Intel or Radeon. Don't say, I should rely on userspace here or
> use fbdev for this.
Just tell the X driver to not use acceleration, and it you won't get
any acceleration used, then you get complete stability. If a driver
writer wants to turn off all accel in the kernel driver, it can, its
not an option we've bothered with for intel or radeon since it really
makes no sense. To put it simply you don't really seem to understand
the driver model around KMS. If no userspace app uses acceleration
then no acceleration features will magically happen. If you want to
write a simple app against the KMS API like plymouth you can now use
the dumb ioctls to create and map a buffer that can be made into a
framebuffer. Also you get hw cursors + modesetting.
> The thing is that the core fbdev API does not expose any acceleration to
> userspace, maybe some drivers do via IOCTLs, but I hope that are only things
> that can be done in a sane way, otherwise I'd consider it a bug. The story is
> different for DRM/KMS, as I understand, as this was primarily for acceleration
> and only recently got modesetting capabilities.
The core drm/kms ioctls don't expose acceleration to userspace either,
again misinformation seems to drive most of your logic. You can't do
generic useful acceleration from the kernel. A lot of modern GPU
hardware doesn't even have bitblt engines.
> It's true that mmap can be PITA, but I don't see any real alternative given that
> you want directly map video memory, especially on low end systems. And there are
> ways around it, you can forbid mapping (though probably most userspace wouldn't
> like it, I guess) or use any other solution like defio.
> If you'd stop exposing the fbdev userspace interface it'd just harden my opinion
> that KMS is a piece of trash and that I should avoid hardware that does not have
> a native framebuffer driver. I think you shouldn't do this, as it's just a
> disadvantage for your end users, but I personally do not really care.
We've fixed this in KMS, we don't pass direct mappings to userspace
that we can't tear down and refault. We only provide objects via
handles. The only place its a problem is where we expose fbdev legacy
emulation, since we have to fix the pages.
Dave.
^ permalink raw reply
* Re: Proposal for a low-level Linux display framework
From: Florian Tobias Schandinat @ 2011-09-17 19:06 UTC (permalink / raw)
To: Dave Airlie
Cc: Rob Clark, Felipe Contreras, Alan Cox, linaro-dev, linux-kernel,
dri-devel, Archit Taneja, linux-fbdev
In-Reply-To: <CAPM=9txHu7mzH8p8g=FmHsjvmAT-aMy-xEFj4odXEvnbs-bhMw@mail.gmail.com>
On 09/17/2011 06:23 PM, Dave Airlie wrote:
>>
>> Is it? Well, okay, I don't want to use any acceleration that can crash my
>> machine, where can I select it, preferably as compile time option? I didn't find
>> such a thing for Intel or Radeon. Don't say, I should rely on userspace here or
>> use fbdev for this.
>
> Just tell the X driver to not use acceleration, and it you won't get
> any acceleration used, then you get complete stability. If a driver
> writer wants to turn off all accel in the kernel driver, it can, its
> not an option we've bothered with for intel or radeon since it really
> makes no sense. To put it simply you don't really seem to understand
> the driver model around KMS. If no userspace app uses acceleration
> then no acceleration features will magically happen. If you want to
> write a simple app against the KMS API like plymouth you can now use
> the dumb ioctls to create and map a buffer that can be made into a
> framebuffer. Also you get hw cursors + modesetting.
Again, you seem to not understand my reasoning. The "if" is the problem, it's
the kernels job to ensure stability. Allowing the userspace to decide whether it
crashes my machine is not acceptable to me.
I do not claim that it is impossible to write a KMS driver in a way that it does
not crash, but it seems more difficult than writing an fbdev driver.
>> The thing is that the core fbdev API does not expose any acceleration to
>> userspace, maybe some drivers do via IOCTLs, but I hope that are only things
>> that can be done in a sane way, otherwise I'd consider it a bug. The story is
>> different for DRM/KMS, as I understand, as this was primarily for acceleration
>> and only recently got modesetting capabilities.
>
> The core drm/kms ioctls don't expose acceleration to userspace either,
> again misinformation seems to drive most of your logic. You can't do
> generic useful acceleration from the kernel. A lot of modern GPU
> hardware doesn't even have bitblt engines.
I did not say that it is used directly for acceleration, but wasn't the point of
DRM to allow acceleration in the first place?
>> It's true that mmap can be PITA, but I don't see any real alternative given that
>> you want directly map video memory, especially on low end systems. And there are
>> ways around it, you can forbid mapping (though probably most userspace wouldn't
>> like it, I guess) or use any other solution like defio.
>> If you'd stop exposing the fbdev userspace interface it'd just harden my opinion
>> that KMS is a piece of trash and that I should avoid hardware that does not have
>> a native framebuffer driver. I think you shouldn't do this, as it's just a
>> disadvantage for your end users, but I personally do not really care.
>
> We've fixed this in KMS, we don't pass direct mappings to userspace
> that we can't tear down and refault. We only provide objects via
> handles. The only place its a problem is where we expose fbdev legacy
> emulation, since we have to fix the pages.
I guess we could do the same in fbdev. It's probably just that nobody is
interested in it as we do not really care about memory management.
Best regards,
Florian Tobias Schandinat
^ permalink raw reply
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox